19920 GMC Sonoma 2.8L console starts to smoke when switch is in any position that has the A/C off

smoke
airconditioning

#1

Car: 1992 GMC Sonoma 2.8L Manual
Miles: ONLY 197,000 miles
Name: Goes by the name of lucky (see http://community.cartalk.com/discussion/2300343/1992-gmc-sonoma-2-8l-sometimes-wont-start-not-even-turn-over-when-engine-is-warm#latest and http://community.cartalk.com/discussion/2300344/1992-gmc-sonoma-2-8l-windshield-wipers-stop-in-middle-and-or-keep-going-a-few-cycles#latest)
Symptom: When ever I put the switch to OFF or VENT or HEAT the console starts to smoke (if the truck is on, of course). I noticed that I can hear the A/C running even when I put switch to one of the off positions.

Fixes: I have not had a mechanic take a look at this yet. They usually complain about other things when I bring it in. Little things like “your brakes are almost gone” (big deal, I don’t need breaks because it is a stick shift) or “your tires are showing their metal wire” (big deal, I’ve had a front tire blow out before at 70 mph… on this same truck come to think of it).

Current work arounds: I keep the A/C on all the time even if I don’t need it. I tried pulling the fuse and that did work, I can put the switch anywhere without the fear of smoke but it turns off the blower motor as well. If the blower is off then I’ll have a hard time getting heat in the winter (Florida winters are very cold, down to the low 40s sometimes)

Feeble attempt to diagnose: I think I’ve seen card board be used as insulation inside the console before, I think whatever insulation was in there started degrade. I’m thinking that I’d like to track down the wires for and put the A/C on a different switch so I can still turn off the A/C and keep the blower going for the cold cold winter. Are there simpler solutions?


#2

Wow, lousy brakes, bad tires, and the possibility of it catching fire. Sounds great. Glad you won’t be driving or parking near me.

What fuse did you pull? The blower motor one or something else? Has any wiring work been done on the vehicle in the past, such as the installation of an after market stereo or alarm, or another repair? I would take the console apart and see where the smoke is coming from/does anything look burnt, and are there any wires with frayed/scraped insulation contacting metal. Same with the “head” unit in the dash that controls the HVAC.


#3

My only guess is that the blower motor may be overheating. The blower may be on low all the time by design to keep air flowing through the cabin. On my 1978 Oldsmobile, there was a cooling tube that went from the air duct to the blower. Perhaps the cooled air helps keep the temperature of the motor down.
I would recommend that you leave the fuse out. Only wimps need heat in the cabin. You are obviously no wimp if you drive with bad brakes and tires that have the steel belts showing.


#4

Stuff all the cardboard into trhe console that you can…it’s great tinder. Once all that pesky carpet and wire insulation is burnt off, you can trace those wires right to the source.

The AC is supposed to cycle on and off.

I’d pull up the console and find out what is burning.
We had a case a few months ago that was an ongoing blowing fuse problem and the people took a trip with the car anyway. Last we heard from them they were stuck away from home having to rely on a mechanic they didn’t know and needed a lot of work on the burnt up harness.

Stuck far from home and work.

Yosemite


#5

well at least your honest ben. I ve been in situations, where it was necessary for me to drive a vehicle that wasn t safe too. it s really important to drive gently when your car is crap. you might hurt someone. or kill them.

just fix the brakes and leave the heat off until you can find another car.

my truck hasn t had heat for years and it got to minus 14 here last year, you ll be ok

from all the threads, I d say this Sonoma is no more.