1991 Toyota truck heater problem
LucifinaMae
work. The guy I bought it from told me that there's a problem with the
blower...he said it needed a new heater fan resister, I think? The blower
works, but only on high, otherwise it stays off. Besides that, it only blows
cold air. I've located the heater core and I'm certain that I can change it
myself if that's what's needed, but I think that it may just be the
thermostat....So basically there's two problems:
1) The blower isn't functioning properly. What do I need to fix it?
2) No hot air comes out when the heater is turned on. Thermostat problem or
heater core, and how can I tell which one it is?
Jeff Strickland
The resistor pack is open in all speed settings except High. It is a common
part that should be available at the parts store down on the corner.
Blowing cold is a sign that the coolant is not circulating through the
heater. Either the plumbing is clogged or the water pump impeller is worn
out. If the impeller is worn, you should also notice that the truck (engine)
gets hot while stopped in traffic, then cools again when the truck gets
going. My money is on clogged plumbing.
You can clear the plumbing by disconnecting the heater hoses and connecting
a garden hose to one and turning the hose on. This will flush clear water
through the heater core and hoses. You could, and probably should, flush the
entire cooling system.
"LucifinaMae" <u41643@uwe> wrote in message news:80478e38cffcc@uwe...
Mike
"LucifinaMae" <u41643@uwe> wrote in message news:80478e38cffcc@uwe...
Blower motor resister is bad. The reason the blower motors works on high
speed is that the resister is not used for full speed.
Do you have an engine temp gauge on the dash ? If so, the pointer should be in
the middle of the scale when warmed up, if the thermostat is working
correctly. If the gauge reads lower or stays around the cold mark your
thermostat is stuck open or the wrong temp for the truck.
You could also have a plugged heater core. With the engine warmed up open the
hood and feel the hoses going to the heater core. Both hoses should be hot,
which would indicate coolant flow. If the hoses were cold it would indicate no
flow. I believe you also have a hot water valve in one of the hoses that is
worked by a cable. Makes sure the cable is connected and that it moves when
you slide the temp control from hot to cold. If you have little to no flow in
the heater core you may be able to remove both hoses and flush it with a
garden hose.
Mike
"Jeff Strickland" <cr...@verizon.net> wrote in message
news:jXIwj.33484$T8.17184@trnddc03...
> It needs a ballast resistor.
It doesn't use one.
>
> The resistor pack is open in all speed settings except High. It is a common
> part that should be available at the parts store down on the corner.
The blower resistor is not used for high speed.
>
> Blowing cold is a sign that the coolant is not circulating through the
> heater. Either the plumbing is clogged or the water pump impeller is worn
If the water pump were bad the truck would overheat.
LucifinaMae
I do have an engine temp gauge, and it reads really really cold, so it seems
like there must be a problem with the thermostat, which is what I suspected.
However, neither of the hoses from the heater core is hot, so it seems like
the heater core is also plugged. Tomorrow I shall undertake installing a new
thermostat and flushing the heater core. Oh, and the hot water control valve
is connected and moves when the temp control slides from hot to cold...one
thing I don't have to fix, yay!
As for the blower, I just replaced the fuses and the relay, but the blower is
still only working on high. The relay had condensation in it, as did the fuse
area, and both the fuses and relay were corroded. I cleaned everything out
as best I could...is there something wrong with the area the relay plugs in
to? There didn't seem to be any obvious corrosion anywhere else other than
the fuses and relay themselves....Any other ideas?
Jeff Strickland
"Mike" <m...@localnet.com> wrote in message
news:38Kwj.4944$Sa1....@news02.roc.ny...
>
> "Jeff Strickland" <cr...@verizon.net> wrote in message
> news:jXIwj.33484$T8.17184@trnddc03...
>> It needs a ballast resistor.
>
> It doesn't use one.
>
>
Ballast resistor is the functioinal equivelent to the blower resistor.
>>
>> The resistor pack is open in all speed settings except High. It is a
>> common part that should be available at the parts store down on the
>> corner.
>
> The blower resistor is not used for high speed.
>
>
That's correct. The resistor(s) is(are) used for all of the other speeds
except high. This is why the other speeds fail and high remains working.
>>
>> Blowing cold is a sign that the coolant is not circulating through the
>> heater. Either the plumbing is clogged or the water pump impeller is worn
>
> If the water pump were bad the truck would overheat.
>
>
True, mostly.
There are reports of failed impellers that let the engine maintain mostly
normal temps, but the temps rise when airflow slows. This symptom is also
common when the fan clutch fails, but we are not talking about the fan
clutch so I did not mention it earlier because I did not want to get the OP
side tracked. We are not talking about the fan clutch because it will not
affect the heater performance ...
I agree that there would be other symptoms of a worn impeller, heat being
the most significant. But, the impeller can fail where coolant flow through
the heater core is diminished, while flow through the motor is marginable.
If this was the case, temp problems in the motor should crop up soon, if
they are not apparent already. This is why I put my money on the clogged
plumbing to the heater core, or a clogged core itself. My remedy for clogged
plumbing and/or core is to flush with a garden hose. It would be better to
take the truck for a professional flushing because they will properly
capture the coolant that comes out,
You should have read all of my first post, then I would not have had to
explain this all again.
Jeff Strickland
"LucifinaMae" <u41643@uwe> wrote in message news:80498e7ee5a9a@uwe...
You still need the resistor pack. If the fuse was the problem, the fan would
not work at all.
If the truck indicates that the engine is cold, AND the engine really is
cold, then the heater is not going to blow warm. It follows that you have a
t-stat that is either missing or is stuck open. Either of these conditions
will cause the temp guage to indicate cold AND the engine to actually be
cold. Top this with cold temps where you live (Snow Belt, for example) and
the engine can be being harmed by the lack of warmth.
ONE MORE TEST
Find out if the heater is TRYING to blow hot. Select the Vent setting, and
Max heat, and feel if the air is warm or not. If warm, AND you live in the
snow belt, then the heater is trying to work, but the stuck/missing t-stat
is not allowing the heat to rise to a level sufficient to warm the motor or
the cabin. (For this test to work, you need to let the motor run for several
minutes -- the heater in my truck stays on cold for almost the first 2 miles
in the morning, you should see if the heater blows warm after at least 3
miles.
What is the outside temp when you notice the temp guage stays on Cold?
LucifinaMae
>not work at all.
Yes! Definitely the resistor pack. Two of the coils are broken and the
ceramic running along all of them are broken and missing.
>ONE MORE TEST
>Find out if the heater is TRYING to blow hot.
The heater does nothing but blow really cold air directly into the cab. I
live in Northern California, below snow level but certainly cold. The
outside air temp has ranged between the 50's up to low 70's when I've been
driving. It does seem that the truck's temp gauge registers colder when it's
colder, but it hasn't gotten into a normal operating range since I bought it.
Right now it's 46 degrees, I drove the truck earlier today and just had it
warmed up in the driveway for over 5 minutes, but to no avail; the air
blowing into the cab is the same temp as the air outside....
Bruce L. Bergman
>>You still need the resistor pack. If the fuse was the problem, the fan would
>>not work at all.
>
>Yes! Definitely the resistor pack. Two of the coils are broken and the
>ceramic running along all of them are broken and missing.
When you replace the resistor, keep an eye on the heater blower
motor function itself. If the motor is flaky because of worn brushes
or bad bearings it'll start fine then quit after running a while.
The combination of locked-rotor current from the stalled motor and
no cooling fan airflow blowing over the coils of the resistor pack
will quickly burn up the new resistor pack. A very expensive way to
stop the motor current.
>>ONE MORE TEST
>>Find out if the heater is TRYING to blow hot.
>
>The heater does nothing but blow really cold air directly into the cab. I
>live in Northern California, below snow level but certainly cold. The
>outside air temp has ranged between the 50's up to low 70's when I've been
>driving. It does seem that the truck's temp gauge registers colder when it's
>colder, but it hasn't gotten into a normal operating range since I bought it.
>Right now it's 46 degrees, I drove the truck earlier today and just had it
>warmed up in the driveway for over 5 minutes, but to no avail; the air
>blowing into the cab is the same temp as the air outside....
Thermostat failed open, or missing.
Get the new t-stat at the dealer - there are minor visible
differences between the aftermarket ones that make major operational
differences if you use the wrong unit... And they can be installed
backwards, so read the Service Manual.
Note that sometimes people remove the t-stat to "fix" (mask) another
problem like a badly clogged radiator or an eroded water pump. Don't
be too surprised if you fix one problem and find another.
--<< Bruce >>--
Anyolmouse
"LucifinaMae" <u41643@uwe> wrote in message news:80478e38cffcc@uwe...
After reading all of the posts I agree with Bruce Bergman's post, but
would like to add that the heater valve could be a problem too. I had
that problem with an '87 that I bought some years ago. But, you wont
know until you get the engine up to temperature and still don't have
heat. Unless, you take the hose lose from the heater valve and the other
side of the heater and flush water through it.
--
Anyolmouse
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LucifinaMae via CarKB.com
> When you replace the resistor, keep an eye on the heater blower
>motor function itself. If the motor is flaky because of worn brushes
>or bad bearings it'll start fine then quit after running a while.
>
> The combination of locked-rotor current from the stalled motor and
>no cooling fan airflow blowing over the coils of the resistor pack
>will quickly burn up the new resistor pack.
Should I just open up the motor and check it while I'm under here? Seems
like a pain in the butt, but better now than a thousand miles down the road
and having to get at everything again anyway. Besides, it seems like finding
a resistor pack is going to be near impossible...I've already gone to both
wrecking yards in my little town, and all the packs we found were already
broken, so I definitely don't want to burn up the new one, when I finally
find it. Anybody know of a place to look on-line?
Thanks for the tip about the t-stat....I was just going to go to Napa, but I
guess I'll head to the dealer after all.
> Note that sometimes people remove the t-stat to "fix" (mask) another
>problem like a badly clogged radiator or an eroded water pump.
The radiator was replaced a couple of years ago, but peering inside it looks
like I need to get the whole coolant system flushed instead of just the
heater core like I was planning, so I guess I'll drive her in to the
professionals for that so they can deal with the coolant...although it
doesn't seem like the proper ratio of water and coolant was used, as there
isn't a really pungent coolant smell when the radiator cap is open. How would
I know if the water pump is eroded?
--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/toyota-truck/200802/1
Handyman
You can get the resistor pack through www.rockauto.com, I believe they
carry them by several manufacturers.
Mike
"LucifinaMae via CarKB.com" <u41643@uwe> wrote in message
news:80548bc83dcdc@uwe...
You would have overheating problems.
Bruce L. Bergman
<u41643@uwe> wrote:
>Thanks Bruce...now just a few more q's.... :)
>
>> When you replace the resistor, keep an eye on the heater blower
>>motor function itself. If the motor is flaky because of worn brushes
>>or bad bearings it'll start fine then quit after running a while.
>>
>> The combination of locked-rotor current from the stalled motor and
>>no cooling fan airflow blowing over the coils of the resistor pack
>>will quickly burn up the new resistor pack.
>
>Should I just open up the motor and check it while I'm under here? Seems
>like a pain in the butt, but better now than a thousand miles down the road
>and having to get at everything again anyway.
Rank that as "Royal Pain", because once you check or change the
brushes and clean & grease the bearings, you have to get the case
together and closed again.
They usually have an obvious trick for keeping the brushes retracted
as you put it back together (if you know to look for it), usually
involving a strategically placed hole and a length of music wire - or
a straightened out paperclip - to hold or "cage" the brushes in the
retracted position as you slide the case halves back together. Once
it's together you pull the wire and that releases the brushes.
> Besides, it seems like finding
>a resistor pack is going to be near impossible...I've already gone to both
>wrecking yards in my little town, and all the packs we found were already
>broken, so I definitely don't want to burn up the new one, when I finally
>find it. Anybody know of a place to look on-line?
The heater blower resistor is probably going to be a Dealer Only
item, search around for dealers with an online presence that will
discount them. As you've found, they are too popular at junkyards.
Don't worry /too/ much about killing the new one - just be aware and
alert that the motor can stop when it shouldn't, and kill the heater
power fast if/when you notice it has stopped.
>Thanks for the tip about the t-stat....I was just going to go to Napa, but I
>guess I'll head to the dealer after all.
>
>> Note that sometimes people remove the t-stat to "fix" (mask) another
>>problem like a badly clogged radiator or an eroded water pump.
>
>The radiator was replaced a couple of years ago, but peering inside it looks
>like I need to get the whole coolant system flushed instead of just the
>heater core like I was planning, so I guess I'll drive her in to the
>professionals for that so they can deal with the coolant...although it
>doesn't seem like the proper ratio of water and coolant was used, as there
>isn't a really pungent coolant smell when the radiator cap is open. How would
>I know if the water pump is eroded?
I just change the pump on mileage if it hasn't failed of natural
causes (seal and/or bearing) by 120K miles.
On cars with a timing belt, or worse where the timing belt drives
the water pump, change the pump every time you change the timing belt.
It should go every other, but since you are already right there to do
the timing belt that's not the way to bet.
--<< Bruce >>--
Jeff
> On Tue, 26 Feb 2008 23:23:01 GMT, "LucifinaMae via CarKB.com"
> <u41643@uwe> wrote:
>
>> Thanks Bruce...now just a few more q's.... :)
>> Besides, it seems like finding
>> a resistor pack is going to be near impossible...I've already gone to both
>> wrecking yards in my little town, and all the packs we found were already
>> broken, so I definitely don't want to burn up the new one, when I finally
>> find it. Anybody know of a place to look on-line?
>
> The heater blower resistor is probably going to be a Dealer Only
> item, search around for dealers with an online presence that will
> discount them. As you've found, they are too popular at junkyards.
The dealer is not the only option. Kragen, Autozone, and NAPA all have
listings for Toyota heater blower motor resistor packs.
LucifinaMae via CarKB.com
>carry them by several manufacturers.
Awesome! They do have them, and for cheaper than elsewhere. Thanks!
--
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