[GMCnet] Generator light on ... alternator is charging...

[Alan M DeLuccio]

Greetings,

The 100 amp alternator on my 78 Royale is putting out 13+v, and yet the GEN light on the dash is on. The belt is tight and the connections are clean.
Has anyone had this problem? Is there a relay or??? that might be faulty ... and Where might it be located? Any help would be greatly appreciated of
course.

Thanks,
--
AMDGMCMan
Alan M DeLuccio
78 Royale with
Coachmen,Center Kitchen Floorplan
09 Harley Davidson Street Glide
65 Corvair Monza Convertible
96 RAV4 2 door Manual 4WD
Long Beach, CA


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[Thomas Phipps]

When you say 'on,' do you mean bright or dim amount of light? Different answers.
Tom, MS II
--
1975 GMC Avion
KA4CSG

[gene Fisher]

--
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

[gene Fisher]

Do you have an APC .?

Read my tag line

On Sun, Feb 5, 2017 at 11:37 AM Thomas Phipps <tph...@outlook.com> wrote:

--
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

[gene Fisher]

On Sun, Feb 5, 2017 at 11:44 AM gene Fisher <mr.er...@gmail.com> wrote:

>
>
> Do you have an APC .?
>
> Read my tag line
>

Or read here

http://www.gmcmotorhome.info/engine.html#alternator

[Alan M DeLuccio]

I have/had been using an APC. The light came on while it was installed. I removed it ... tightened and cleaned everything, but when removing the APC
the tab/clip on the connector on the side that connects to the alt broke off, so I have not reinstalled it.

[gene Fisher]

On Sun, Feb 5, 2017 at 12:17 PM Alan M DeLuccio <delba...@gmail.com>
wrote:

--
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

[Alan M DeLuccio]

The steering boot(s) also need replacement. There are 2 types offered at Applied. The Al Ferrara's Steering Boot Kit and the GM16-STBOOT. Does anyone
have experience with these 2 kits? Is one an easier install than the other. I changed mine out about 10 years ago and it was a pain.

[Ken Burton]

Output of the alternator should be around 14.7 volts if you are reading it at the alternator or at the center post of the isolator. If read after the
isolator it should be 13.8 to 14.2 vDC.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Bill Wevers]

http://www.gmcmotorhome.info/engine.html#alternator
http://www.gmcmotorhome.info/engine.html#alternator
--
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose

[Tony Cook]

Sign of your alternator going out. My indicator was glowing dim even with the APC cable installed . Alternator finaly died R&R'd and no more glow.
--
Tony Cook
77' Kingsley ' SuperSession 77 '
Torrance Beach,CA

[Jerry Burt]

amdgmcman wrote on Sun, 05 February 2017 12:34
> The GEN light is DIM ...not Bright


A quick and easy check before you get too involved:
If you read down low enough on the gmcmotorhome.info links people have posted, you'll see a blurb about checking the dash lights fuse on the panel in
the glove box. Mine was blown and replacing it was the cure for me when my light did that.
--
Patti & Jerry Burt
73 Gmc 26' Canyon Lands -
Photos - http://jburt.smugmug.com/GMC-Motorhome
Lots of upgrades but lots to do to make it ours.
Members: FMCA - GMCMI - GMCWS - Pacific Cruisers - 49ers

[A.]

amdgmcman wrote on Sun, 05 February 2017 12:24

> Greetings,
> The 100 amp alternator on my 78 Royale is putting out 13+v, and yet the GEN light on the dash is on. The belt is tight and the connections are
> clean. Has anyone had this problem? Is there a relay or??? that might be faulty ... and Where might it be located? Any help would be greatly
> appreciated of course.
>
> Thanks,

If not already done, get and install an APC from Mr. ERF. Then, if that doesn't fix it, post back here.
http://gmcmotorhome.info/APC.html
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"When I grow up I am going to be a curmudgeon."

[Alan M DeLuccio]

Greetings,

Can an APC go bad? I have had one installed on my GMC for quite a few years and just recently the GEN light has come on. Dim ... but on. It is a 78,
and I read that GM solved a problem in later models that occurred on earlier models that caused the GEN light to glow dim.The GEN is putting out
voltage ... approx 13 volts, so maybe the APC is bad? I had an 100 amp Alternator installed by Miguel at MGM in 2014, so I'm hoping it is not bad.

Comments and suggestions appreciated.

Thanks,

--
AMDGMCMan
Alan M DeLuccio
78 Royale with
Coachmen,Center Kitchen Floorplan
09 Harley Davidson Street Glide
65 Corvair Monza Convertible
96 RAV4 2 door Manual 4WD
Long Beach, CA

[gene Fisher]

Your earlier post said you removed it
Barton told you the alternato volts should be 15 volts
Read here
http://www.gmcmotorhome.info/engine.html#alternator

Is prob not the APC

On Fri, Mar 24, 2017 at 9:00 PM Alan M DeLuccio <delba...@gmail.com>
wrote:

> Greetings,

--
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

[A.]

Mr ERFisher wrote on Sat, 25 March 2017 08:01

> Your earlier post said you removed it
> Barton told you the alternato volts should be 15 volts
> Read here
> http://www.gmcmotorhome.info/engine.html#alternator
>
> Is prob not the APC

15V sustained is too high, except in sub-zero tempeatures. But 13.6V minimum, generally. More than 14 after a long starter crank.

--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"When I grow up I am going to be a curmudgeon."

[A.]

A Hamilto wrote on Sat, 25 March 2017 10:57

> Mr ERFisher wrote on Sat, 25 March 2017 08:01
> > Your earlier post said you removed it
> > Barton told you the alternato volts should be 15 volts
> > Read here
> > http://www.gmcmotorhome.info/engine.html#alternator
> >
> > Is prob not the APC
> 15V sustained is too high, except in sub-zero tempeatures. But 13.6V minimum, generally. More than 14 after a long starter crank.

Oops. Forgot about the 0.7V drop across the isolator. 15V is not too high.

[John R. Lebetski]

He needs to tell us how and where he is metering. 13.6-14.2 is ok after the isolator. Where the 13 is metered is important as the sense to the
alternator is after the isolator and 13 minus .7 would cause the lamp to glow.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[gene Fisher]

Here is the bible, do this
http://www.gmcmhphotos.com/photos/data/15/GMC_charging_system_checkout.pdf

On Sat, Mar 25, 2017 at 2:49 PM John R. Lebetski <gransp...@gmail.com>
wrote:

--
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

[Alan M DeLuccio]

A bench test performed on the alternator showed that a diode was bad. After dimantling it and further investigation the capacitor was defective as
well. I also noticed that the unit had an unusual whine since it was installed. Needless to say I replaced it & all is well.

--
AMDGMCMan
Alan M DeLuccio
78 Royale with
Coachmen,Center Kitchen Floorplan
09 Harley Davidson Street Glide
65 Corvair Monza Convertible
96 RAV4 2 door Manual 4WD
Long Beach, CA

[John R. Lebetski]

A bad diode will cause 1 of 3 phases to be missing. The "gap" in output will cause louder whine. This may have taken out the filter cap is my guess.

--
John Lebetski
Woodstock, IL
77 Eleganza II