[GMCnet] dash air

[Glover]

I bought my motorhome 2 years ago and the dash air has never worked ? I am just now getting into it and would like anyones input on it ? I just now
started messing with it so havent got a lot to offer yet !? nothing works ? only thing I have done so far is check the fuse and it is good. I know
Im not offering much information yet, but as always know you guys have great insight into anything GMC !

thanks,

Brian
--
Brian G.
Griffin Ga.
1978 Eleganza II
TZE168V101637


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[Ken Burton]

Well, If nothing works, the first thing you need to do is get the fan running. You can troubleshoot the fan even if the compressor is not running.

The next thing to do is see if the compressor is running. Put the system on full cold and the fan on full speed and see if the compressor clutch ever
energizes.

If it does not energize you need to decide if it is an electrical problem or a refrigerant charge problem.

Pull the connector off of the pressure switch and short the connector pins with a paper clip. Start the engine with the AC on and see if the clutch
energizes.

If it does, REMOVE the Jumper. You do not have an electrical problem.

Now you are down to a refrigerant charge problem. You need to get a gauge and see if there is any refrigerant in the system. If it is low or empty
you need to recharge it. I strongly suggest any recharge be done with Duracool. If you get this far and need to recharge, post again and one of us
will help you with the recharge.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Glover, Brian K.]

Thanks, Ken

I was thinking of pulling the unit out of the dash to check for power ? because when I say nothing is working I mean nothing ?! no sounds at all no clicking or fans or anything ? I wonder if the dash air unit itself is dead ? and do you think you could pick one up at a junk yard ?

Again, I know I have a lot to look into, but I always like to get yalls input on how to start !

Thanks ,


Brian

[Ken Henderson]

Brian,

The "other Ken" here 'cause I'm already up.

First off, forget replacing the whole unit from a junk yard -- ain't no
direct replacement. Besides, there's probably nothing major wrong with
yours.
,
Secondly, you need to tell us what year coach it's in -- there are 3
distinctly different HVACs in GMCs.

Thirdly, you need to download and study
http://gmcws.org/Tech/air_conditioning/air_conditing.html, the
authoritative source for upgrading GMC A/C.

Fourthly, Ken B. forgot to mention one thing when he told you to turn the
A/C blower to Hi for your initial test: The engine MUST be running for the
fan to run in Hi -- it's fed directly from the alternator, not the battery,
in that position. In all other speeds, there's a relay involved, which
sometimes fails.

Fifth, follow Ken B.'s instructions first of all.

Ken H.


On Mon, Jul 25, 2016 at 6:54 AM, Glover, Brian K. <BKGl...@southernco.com>
wrote:

[Glover, Brian K.]

Thanks other Ken !

1978 Eleganza II

I will look through the info you've provided.

Thanks
Ken

Sent from my iPhone

[Emery Stora]

Ken
In his first message he says in his signature line that it's a 1978 Eleganza Ii


Emery Stora

[Rob Mueller]

Brian,

I'm going to demonstrate an acute grasp on the obvious and suggest you get a copy of X-7525 and read/study section 1 -
Air-Conditioning. This will give you a good grasp on the basics of the system, that way when "we" make recommendations you won't be
lost.

The good news is that you have a 1978 GMC and they have the best of the worst (so to speak).

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of Glover

I bought my motorhome 2 years ago and the dash air has never worked ? I am just now getting into it and would like anyones input on
it ? I just now started messing with it so havent got a lot to offer yet !? nothing works ? only thing I have done so far is check

the fuse and it is good. I know I'm not offering much information yet, but as always know you guys have great insight into anything
GMC !

thanks,

Brian

[Glover, Brian K.]

Rob,

I have a manual printed out X7120A PN. 2028572.
Doesn't really give you any great detail, I will look up the manual you are referencing so I can get a better understanding of operation.

Thanks,
Brian

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of Rob Mueller
Sent: Monday, July 25, 2016 5:28 PM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] dash air

[John Wright]

What is the X-7120 manual? I cannot seem to find it on the list of maintenance manuals. The Type 2 air package was the best of all the systems installed in the GMC. The type 2 system in my 77 coach would absolutely frost you out and required a small blanket on the legs. DO NOT start tearing stuff up, do the check to eliminate and find your problems. You have gotten good advice here already. Give us your results and ask more questions. What ever you do, DO NOT put R-134 into your system!

JR

[Jim Kanomata]

When you state that the unit does not work, it does not mean much.
Does the vent fan work?

On Mon, Jul 25, 2016 at 6:10 AM, Glover, Brian K. <BKGl...@southernco.com>
wrote:

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Glover, Brian K.]

Nothing works ,, you can move all the controls and there is no noise of any kind or no sign of operation.



Sent from my iPhone

[A.]

Glover, Brian K. wrote on Mon, 25 July 2016 05:02

> I bought my motorhome 2 years ago and the dash air has never worked ? I am just now getting into it and would like anyones input on it ? I just
> now started messing with it so havent got a lot to offer yet !? nothing works ? only thing I have done so far is check the fuse and it is good. I
> know Im not offering much information yet, but as always know you guys have great insight into anything GMC !
>
> thanks,
>
> Brian

It probably has some corroded connections. My Sequoia had a connection out of the blower relay that a PO spliced poorly and once I cleaned and
soldered that, mine blows all speeds. Get the wiring diagram from here and start checking continuity (AC/Heater is at the bottom):

http://www.bdub.net/wirediagrams/78-chassis-electrolevel-II.pdf

Everything outside is on the firewall and the blower box, easy to get to. You might need to carefully remove the dash control to check connections to
it.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."

[Glover, Brian K.]

Thanks, I will take a look this evening and see if I can come up with something.

Thanks,

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of A.
Sent: Monday, July 25, 2016 1:32 PM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] dash air

[Ken Burton]

You need to get the fan working First. It is used for both the heater and the AC. Download the wiring diagram as a start. The most common items to
fail in the fan circuit are:
1. The fuse (please note: Beside the fuse in the normal fuse panel, there is a separate fuse or fusible link under the hood just for the full speed
fan position.
2. The fan motor (available from Auto Zone)
3. The fan relay
4. Burned / bad connections on the fan relay
5. The ground wire on the fan motor which is mounted to the metal containing the fan.

There are other things in the circuit that can fail but the above are the most common things and all are easy to diagnose and replace.

So get out a volt meter and the wiring diagram and start probing.

Colonel Ken mentioned something that is important and I did not mention earlier. When diagnosing the fan circuit, the full speed position requires
the engine alternator to be running. You can troubleshoot the other slower speeds with the key on and the engine not running.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Terry]

Don't forget the blower resistor assembly. The high speed relay AND the resistor were both inoperative on mine when I got it, in addition to the
connections on the relay being kinda toasted. The resistor being broken will stop the blower from operating in the slower speeds.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

[Terry]

Don't forget the blower resistor assembly. The high speed relay AND the resistor were both inoperative on mine when I got it, in addition to the

connections on the relay being kinda toasted. The resistor being broken will stop the blower from operating in the slower speeds. In addition to that,
the fuse box connection sometimes loses continuity due to 40 years of oxidation on the fuse retainer clips.

--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

[Ken Burton]

I intentionally did not list the resistor or the switch. I do not want to overwhelm him with too many possibilities. I figured once we get him in
there with a meter or test light we can bring those items into the mix if the readings indicate they could be a problem. I gave him the most common
stuff to look at whit his meter.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Chris S.]

Just wanted to add that once you get the blower/fan system working, do not scrap the old AC system until it's been checked over. It could just need a
simple leak fix and/or recharge. We ended up staying with the old system on R-12 after thinking about upgrading to R-143a but it ended up just
needing a leak fix and recharge, and ever since has been working great. The old system, as the guys on here told us, is very good and you get COLD
air. Duracool is another solution that seems to also work well without having to upgrade the system.
--
Chris S. -
77 Kingsley mostly OEM -
S.E. Michigan

[Nathan Cline]

I will be posting a howto soon for those who would like to recharge their A/C with propane/isobutane the easy way, and tune the system for maximum
cooling. Waiting on some parts to come in to get mine charged up first.
--
Gadsden, AL

[John R. Lebetski]

I would suggest learning automotive HVAC on a junk 1978 GM vehicle. They are all pretty much the same with a given year stamp. They all have the same
electrical issues after all these years. They can work like new if you know how to do it. There are electrical systems, simple mechanical systems
(temp door cable) a whole system of vacuum operated motors and valve, and the refrigeration system itself. And don't forget a working fan clutch is
part of the AC system.
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First

[kelly stockwell]

Our dash air worked when I got the rig 6 weeks ago but didn't work the last time out.
The PO had it checked and recharged just before bringing it to us (for $300) they found no leaks but had some comment about the system being designed
for a different size molecule and it needing recharging. I don't remember on what basis.

Can I get one of those recharging units at Bond auto parts and do this myself?

the blower works fine, it's just not cold air anymore. It seems like the compressor turns on as I can feel the engine running it.

kelly
--
1978 Kingsley
Putney VT

[Matt Colie]

kstockwell wrote on Wed, 27 July 2016 08:08

> Our dash air worked when I got the rig 6 weeks ago but didn't work the last time out.
> The PO had it checked and recharged just before bringing it to us (for $300) they found no leaks but had some comment about the system being
> designed for a different size molecule and it needing recharging. I don't remember on what basis.
>
> Can I get one of those recharging units at Bond auto parts and do this myself?
>
> the blower works fine, it's just not cold air anymore. It seems like the compressor turns on as I can feel the engine running it.
>
> kelly

Kelly,

You do not have a Harbor Freight in striking distance, but you could do an online order of a vacuum pump and gauge set. That is all you really need.
You could get them at Bond (I just looked), but the even with the shipping cost, Hazard Fright is a better deal.

As to the different sized molecule, yes, it was. But the real problem is that the new "environly friendly" R-134 is junk. As a resident of the east
coast, you may be prevented from using HC-12. You also may not legally recharge it yourself, but I didn't live in Vermont, just Maine, Massachusetts
(Mass a Taxes) and dis- Connecticut. They all had lots of laws to get around.

When you do recharge it, get a can with dye in it and a cheap UV light. That way, you might find the leak and fix it.

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit

[gene Fisher]

Read here
http://gmcmotorhome.info/heat.html#duracool

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Billy Massey]

Also see Emerys excellent tutorial
http://www.bdub.net/Duracool_in_your_GMC.pdf

On Jul 27, 2016 8:05 AM, "gene Fisher" wrote:
>
> Read here
> http://gmcmotorhome.info/heat.html#duracool

[Nathan Cline]

If you want to charge with propane/isobutane but Duracool isn't available in your area due to the safety Nazis, or if you'd like to experiment with
different percentage blends, there is a super easy way to do it. It costs about $60 for the fittings (not counting the gauge set), and $8-13 for the
refrigerant itself, which you can buy at Academy Sports or other similar store in your area which carries MSR IsoPro camp fuel. IsoPro is 80/20
isobutane/propane and costs $10/lb. You supplement that with a regular $3/pound bottle of Coleman propane camp fuel to get the desired ratio of
propane to isobutane. I'll do a full writeup next week when a few needed supplies arrive from Amazon. In the mean time I've already experimented with
a rough charge on my '78, and with very little work had it blowing high 30s out the vents on a 100 degree day. My final goal is 35* vent temps.

Speaking of gauge sets, please don't encourage the Chinese junk importers by buying anything from Harbor Freight. You can get better stuff off
Amazon.com which may also be of Chinese origin, but at least you can check out the reviews to figure out what's good or junk.


--
Gadsden, AL

[Rob Mueller]

Nathan,

Harbor Freight has reviews on their website as well. Here's the 1/2" impact wrench I have that I found to be good.

http://www.harborfreight.com/12-in-professional-air-impact-wrench-68424.html

If you click on the link and look to theright of thr 4 1/2 stars you will find 476 reviews. When you click on Read 476 reviews the
first page is a summary that notes Pros Cons Best Uses.

Here's the two A/c gage sets they sell:

http://www.harborfreight.com/ac-r134a-manifold-gauge-set-60806.html

http://www.harborfreight.com/ac-r134a-manifold-gauge-set-62707.html

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of Nathan Cline
Sent: Thursday, July 28, 2016 1:13 AM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] dash air

[Nathan Cline]

I bought a water pump from the local HF store a couple months ago that seized up after only 4-5 uses. $40 down the drain. Never again will I
financially support that company.

[Emery Stora]

> On Jul 27, 2016, at 9:12 AM, Nathan Cline <nathan....@gmail.com> wrote:
>
> If you want to charge with propane/isobutane but Duracool isn't available in your area due to the safety Nazis, or if you'd like to experiment with
> different percentage blends, there is a super easy way to do it. It costs about $60 for the fittings (not counting the gauge set), and $8-13 for the
> refrigerant itself, which you can buy at Academy Sports or other similar store in your area which carries MSR IsoPro camp fuel. IsoPro is 80/20
> isobutane/propane and costs $10/lb. You supplement that with a regular $3/pound bottle of Coleman propane camp fuel to get the desired ratio of
> propane to isobutane. I'll do a full writeup next week when a few needed supplies arrive from Amazon. In the mean time I've already experimented with
> a rough charge on my '78, and with very little work had it blowing high 30s out the vents on a 100 degree day. My final goal is 35* vent temps.
>
> Speaking of gauge sets, please don't encourage the Chinese junk importers by buying anything from Harbor Freight. You can get better stuff off
> Amazon.com which may also be of Chinese origin, but at least you can check out the reviews to figure out what's good or junk.
>
>
> --
> Gadsden, AL
>

Duracool is available everywhere if you order it on the Internet. They can quickly ship it to you.
The 80/20 blend that you mention will work but it is not the optimum mixture.

Emery Stora
77 Kingsley
Frederick, CO

[Nathan Cline]

That's why you supplement with a bottle of "pure" propane to bring it to the correct ratio. This also allows you to run a different ratio of propane
to isobutane as desired for one's specific requirements. More isobutane could be helpful in maintaining cooling in extreme heat conditions, due to its
higher critical temperature, whereas more propane should give colder vent temps under more normal conditions. At $8 for a full charge it's way cheaper
than any other option, especially if you plan to reuse the fittings to charge more than one vehicle. Every one of my vehicles will be running this mix
before it's over with. More details and exact procedure will be detailed in the writeup next week. :)


--
Gadsden, AL

[A.]

kstockwell wrote on Wed, 27 July 2016 07:08

> Our dash air worked when I got the rig 6 weeks ago but didn't work the last time out.
> The PO had it checked and recharged just before bringing it to us (for $300) they found no leaks but had some comment about the system being
> designed for a different size molecule and it needing recharging. I don't remember on what basis.
>
> Can I get one of those recharging units at Bond auto parts and do this myself?
>
> the blower works fine, it's just not cold air anymore. It seems like the compressor turns on as I can feel the engine running it.
>

> Here's the word from the PO when he just recharged it.
> I also had the Dash AC recharged. The compressor, replaced by the prior owner for over $800, was cycling more often than last year and the output
> was not super cooled. . The shop confirmed that the new version of Freon was low and needed to be augmented. The molecules of the new stuff are
> smaller than Freon molecules and seep around seals designed in the 70's. The last recharge was 2014. My shop says there is no "leak", but that all
> old systems that have been converted need to be recharged regularly. $360 later we are ready to rock and roll
>
> kelly
I am going to try to give you the best advice of all the confusing posts you have seen in response to this question.

As of June 2014, Vermont did NOT prohibit the use of hydrocarbon-based refrigerants in automotive applications. Furthermore, as of that date, the EPA
did NOT prohibit retrofitting R-134a systems with hydrocarbon-based refrigerants.

That means, if the state and federal laws have not changed since then, and since your system has been converted over to R-134a with the intent of
using it that way, it is perfectly legal for you to replace the refrigerant in your system with Duracool, or similar product, which has a larger
molecule and will not leak down as fast, if at all.

You probably will not be able to find an automotive refrigerant mechanic that will do that, so you will want to do it yourself.

Now go back and find the posts that point you at the tutorials for doing the work yourself and let us know if you have questions.

--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."

[Norman Allinson]

Amazes me that the government worries about a comparatively small amount of propane type refrigerant in a closed system, but has no issue with sitting
a 25Lb bottle of propane on a shelf underneath your 500 degree BBQ.
--
Norm.

[A.]

Norisan wrote on Wed, 27 July 2016 12:38

> Amazes me that the government worries about a comparatively small amount of propane type refrigerant in a closed system, but has no issue with
> sitting a 25Lb bottle of propane on a shelf underneath your 500 degree BBQ.

Lobbyists. The monopoly that owned the industry doesn't want HC-based refrigerants to catch on so they get laws passed to keep it from happening. The
only straw they can grasp is flammability, and politicians are gullible.

--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."

[Keith V]

My mom had her BBQ grill valve leak while in use, yeah that was a flame thrower!

If you ever are in a fighting mood talk to an AC tech about doing your own AC work.
You'd think you are saying you are going to drive a school bus full of kids off a cliff.
Those people are absolutely nuts, they say things like;
"you cant do it, it it's too complicated"
"Its extremely dangerous"
" your family is riding in that car, are you trying to kill them?"
"It's illegal"
"Thats PROPANE! "

So I can build my own car, custom suspension, steering, brakes, 1000hp engine, but I should be worried about the freeking air conditioner??
Whats going to happen, it might not get cold enough? Oh My God!

[Johnny Bridges via Gmclist]

I don't want to argue the heathen Chinee vs Glorious Americans - you get what you pay for from both. I will point out, however, every HVAC tech in
Atlanta I've met - which is a large percentage of them - uses a set of Yellowjacket gauges. They ain't cheap.

--johnny

--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon

[A.]

Keith V wrote on Wed, 27 July 2016 15:25

> My mom had her BBQ grill valve leak while in use, yeah that was a flame thrower!
> If you ever are in a fighting mood talk to an AC tech about doing your own AC work.
> You'd think you are saying you are going to drive a school bus full of kids off a cliff.
> Those people are absolutely nuts, they say things like;
> "you cant do it, it it's too complicated"
> "Its extremely dangerous"
> " your family is riding in that car, are you trying to kill them?"
> "It's illegal"
> "Thats PROPANE! "
>
> So I can build my own car, custom suspension, steering, brakes, 1000hp engine, but I should be worried about the freeking air conditioner??
> Whats going to happen, it might not get cold enough? Oh My God!

Yep. Its odd that they think 18 ounces of propane in the A/C plumbing is death waiting to happen, and don't seem to care about the 20 gallons of gas
in the tank behind the seat.

The lobbyists had a video made where they "simulated" a collision: punched a hole in the line to the evaporator, rigged something electrical to spark
enough to ignite it, and it set the interior of the car on fire.

True story though in Europe where it is legal, an explosion blew the door off a refrigerator in an old couple's house.

[A.]

Glover, Brian K. wrote on Mon, 25 July 2016 11:45

> Nothing works ,, you can move all the controls and there is no noise of any kind or no sign of operation.

After you get the blower blowing and the compressor compressing, you will need to find and fix the problems with the vacuum system that drives the
actuators, and/or the actuators themselves.

GM used a vacuum valve that is full on or (mostly) full off to control the engine coolant to the heater core. They use a "temperature door" to change
the ratio of air that flows over the heater coil to vary the heat (the temp slider on the dash control). There is a cable from that slider to the
lever on the temp door (the lever is outside the blower box). If that one is not doing anything, someone must have disconnected it.

The rest of the sliders energize electrical contacts to turn the compressor on for AC and defrost and not on for vent and heat. They also determine to
which actuator that vacuum is routed for the various settings. If actuators are not moving to change airflow from feet to face to windshield, you need
to dig into the heater/AC vacuum supply and distribution plumbing.

None of it is rocket science, and you will figure it out from the figures in the Maintenance Manual and putting eyes on the live system.

The heater/AC troubleshooting is the kind of stuff that produces a lot of satisfaction for a little effort. Finding a vacuum leak and replacing a
hose, or a single corroded electrical connection cleaned to get an entire system working.

--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."

[Thomas Phipps]

Since you are in Vermont, drive up to Canada. Go to Canadian Tire or Princess Auto and purchase RedTek A/C. It's Duracool with a different label.
Solves your problem. P.S. the molecule is bigger than Freon.
Tom, MS II
--
1975 GMC Avion
KA4CSG

[Ken Henderson]

Glover,

In troubleshooting your HVAC, you may find these diagrams from the service
manual useful. I color coded them to make following them easier:

http://www.gmcmhphotos.com/photos/color-hvac-troubleshooting-charts/p22988-hvac-connection-charts-color-comp.html

http://www.gmcmhphotos.com/photos/color-hvac-troubleshooting-charts/p22990-hvac-diagram-color-comp.html

Ken H.

On Mon, Jul 25, 2016 at 6:02 AM, <Glover> wrote:

> I bought my motorhome 2 years ago and the dash air has never worked ? I am
> just now getting into it and would like anyones input on it ? I just now
> started messing with it so havent got a lot to offer yet !? nothing
> works ? only thing I have done so far is check the fuse and it is good. I
> know
> Im not offering much information yet, but as always know you guys have
> great insight into anything GMC !
>
> thanks,
>
> Brian

> --
> Brian G.
> Griffin Ga.
> 1978 Eleganza II
> TZE168V101637

[kelly stockwell]

Is there anything propane can't do? No wonder Hank Hill was always so content

kelly
--
1978 Kingsley
Putney VT

[kelly stockwell]

thank you, i was going to look up regulations in VT. I'll see what I can find.

no time before leaving today at noon, but when I get back I'll figure out what I need to do, and with the help of you guys do it

kelly


A Hamilto wrote on Wed, 27 July 2016 13:07

> kstockwell wrote on Wed, 27 July 2016 07:08
> > Our dash air worked when I got the rig 6 weeks ago but didn't work the last time out.
> > The PO had it checked and recharged just before bringing it to us (for $300) they found no leaks but had some comment about the system being
> > designed for a different size molecule and it needing recharging. I don't remember on what basis.
> >
> > Can I get one of those recharging units at Bond auto parts and do this myself?
> >
> > the blower works fine, it's just not cold air anymore. It seems like the compressor turns on as I can feel the engine running it.
> >
> > Here's the word from the PO when he just recharged it.
> > I also had the Dash AC recharged. The compressor, replaced by the prior owner for over $800, was cycling more often than last year and the
> > output was not super cooled. . The shop confirmed that the new version of Freon was low and needed to be augmented. The molecules of the new stuff
> > are smaller than Freon molecules and seep around seals designed in the 70's. The last recharge was 2014. My shop says there is no "leak", but that
> > all old systems that have been converted need to be recharged regularly. $360 later we are ready to rock and roll
> >
> > kelly
> I am going to try to give you the best advice of all the confusing posts you have seen in response to this question.
>
> As of June 2014, Vermont did NOT prohibit the use of hydrocarbon-based refrigerants in automotive applications. Furthermore, as of that date, the
> EPA did NOT prohibit retrofitting R-134a systems with hydrocarbon-based refrigerants.
>
> That means, if the state and federal laws have not changed since then, and since your system has been converted over to R-134a with the intent of
> using it that way, it is perfectly legal for you to replace the refrigerant in your system with Duracool, or similar product, which has a larger
> molecule and will not leak down as fast, if at all.
>
> You probably will not be able to find an automotive refrigerant mechanic that will do that, so you will want to do it yourself.
>
> Now go back and find the posts that point you at the tutorials for doing the work yourself and let us know if you have questions.

--

1978 Kingsley
Putney VT

[Bob Solomon]

Ken, you seem to be very knowledgeable on the air issue. My problem seems to be a vacuum issue. Compressor clutch engages, full charge, but I can not
get the heater to disengage when I switch to "Cold". Any suggestion?

[Keith V]

On my coach the heater valve doesn't shut off unless the control is in recric.

[Ken Henderson]

Bob,

I'm not sure what you mean by "cannot get the heater to disengage". Fact
is, if the A/C is operating, the heater is also. Temperature is controlled
by what I call the "damper" -- the cable-operated door which routes blower
air (which has already been through the A/C evaporator) through the heater
core, or not, with some mixing always occurring.

If the cable housing is not firmly clamped to the HVAC box bracket, on the
driver's side of the box, it will slide rather than forcing the cable to
operate the arm attached to the "damper". If you haven't done so, you need
to download the pamphlet, "Separating Hot from Cold", by Zay Brand, from
GMCWS.org, and study it. It tells how to get the most performance possible
from your HVAC, including refurbishing that door.

I don't recall whether Zay suggests it, but an essential part of getting
max cooling from the system is the addition of a positive valve in one of
the heater hoses. I use a ball valve from Lowes to turn off all the water
during warm weather.

If you didn't see the links I sent to Glover for the vacuum lines, let me
know and I'll re-send them. The color coding does make them a lot easier
to follow, IMHO.

Ken

[half.l...@gmail.com]

Hello there (General Kenobi)... Question kinda along the same lines... The blower motor "flow-thru" capacitor on my coach has seen better days, and
I haven't been able to find a replacement. Is this capacitor even necessary, or can I just run a wire from the relay to the motor?
--
Proud owner of a 1975 GMC Glenbrook and a 1991 GMC Syclone... All about the rare birds!

[Emery Stora via Gmclist]

The capacitor is not necessary for the running of the blower motor but it is there to prevent blower motor noise in the radio.
About any capacitor for radio noise reduction can be used. If you look on the side of the capacitor it should show the value. Any capacitor of that value can be used irregardless of the shape.

Emery Stora
emery...@mac.com