AC Control Panel fries out with puff of smoke

[SunlitComet]

got it ... will be back.

 

[wahoo_wes]

hows these?

 

[SunlitComet]

Pretty sure it is the temp circuit so test that out first.

 

[wahoo_wes]

Will do

 

[wahoo_wes]

quick update...

replaced the temp motor actuator and the vent motor actuator under dash, worked ok until i put the fan on high then the panel blew again. Ohmed out all circuits (friend did that and said no shorts found) replacing blower motor and resistor today. fan relay and underhood relay replaced, heater control valve and solenoid replaced

fingers crossed, im running out of will with this thing, 4 panels blown, cant find a short, replacing all the under-dash components, so far i am in for 4 panels, 2 door actuators, the temp valve and solenoid, 2 relays a blower motor and the resistor.

i am rapidly approaching the ultimate solution with this thing (a cliff) we shall soon see....

 

[SunlitComet]

if you are re-using the fan switch and defrost switch, Don't.

 

[wahoo_wes]

nope, all new panels, 3 rotories and 3 pushbuttons, do you mean something else?

 

[SunlitComet]

no just that.

 

[wahoo_wes]

yeah, new panels, about 600 worth now, if this doesnt fix it i will be completely lost. time for something else me-thinks

 

[wahoo_wes]

For anyone this might help out, i did finally find the issue. On the back of the control panel (behind the vent selector knob) is a ribbon connector with a bunch of wires coming out of it.

The issue in this case was the green wire, it runs directly to the PCM under the hood. Somewhere along the run, it must have chafed and shorted out.

Rather than try and pull the entire dash, i simply cut the wire at the PCM and the control panel and spliced in a brand new run. Problem solved.

 

[bux]

Same Issue

WOW, I got on line for the very same issue. I also went through more than one control panel thinking it was no big deal. Now after two, and returning home due to the smell of electronic smoke, I thought I would check this out. Very glad I did. I will look for the same wire and see what I find. I also ordered a new switch hoping I do not need a nel panel AGAIN.
Thanks

 

[wahoo_wes]

yeah well make sure you read this entire thread! LOL, i went through MANY panels, and other parts, before i found that green wire was shorting out somewhere deep in the dash, anyway, its an easy fix. Good Luck!

---------- Post added at 03:56 PM ---------- Previous post was at 03:32 PM ----------

remember to use butt connectors

---------- Post added at 03:59 PM ---------- Previous post was at 03:56 PM ----------

test

 

[My99Yukon]

yeah well make sure you read this entire thread! LOL, i went through MANY panels, and other parts, before i found that green wire was shorting out somewhere deep in the dash, anyway, its an easy fix. Good Luck!

---------- Post added at 03:56 PM ---------- Previous post was at 03:32 PM ----------

remember to use butt connectors

---------- Post added at 03:59 PM ---------- Previous post was at 03:56 PM ----------

test

Old thread but this seems to be a common issue. And it just happened to me a second time this weekend. Before I replace this unit which is only about one year old, give me some insight please into how you ran that wire between the PCM and the heater control module please.

My question is really about how you pulled the wire through and is the wiring harness super tight on the green wire? Can you cut on both ends, splice a wire at the PCM and simply pull the old wire at the control module through the dash until the new splice appears then re-splice at the wire ribbon? Sort of like fishing a heavy gauge wire through a hole by attaching to a coat hanger and thinner wire and pulling through when framing a house?

A few details would be great.

Also, can you repost the diagrams that SunlitComet posted for you? Those images are no longer available. Thanks!

 

[Fless]

Wahoo_wes hasn't been seen since 2011. Think he ghosted.

 

[My99Yukon]

Wahoo_wes hasn't been seen since 2011. Think he ghosted.

Yeah I saw the date of the thread but tagged SunlitComet so thought I could revive the thread since this seems to be a common issue.

I found a diagram for the PCM/VCM and I am not sure if he was talking about this in his thread. It seems like a hell of a chore to run a wire through that harness, if that is even the issue for my rig.

 

[YukonGTmaster]

I started my truck up after a big snow, and the snow melted and ran down through a panel underneath the black defrost grill on the passenger side. If you pull that grill, you will see an oval panel that is siliconed at factory. If the seal cracks, your blower motor duct is directly underneath. My duct filled with water, and as soon as I turned on the fan, electrical smoke! I replaced the blower motor, but still had issues. I ordered the climate control panel from GM, and as I was replacing it, I notice the connector behind had absolutely melted itself. GM sells the connector harness, you just have to cut the old one, and butt splice. If you hear your fan making a squeaking noise, it is very likely moisture in the duct.

 

[tokedigital]

So what you are saying is water is shorting the fan switch to the point of melting 3rd ac control

 

[YukonGTmaster]

Old thread but this seems to be a common issue. And it just happened to me a second time this weekend. Before I replace this unit which is only about one year old, give me some insight please into how you ran that wire between the PCM and the heater control module please.

My question is really about how you pulled the wire through and is the wiring harness super tight on the green wire? Can you cut on both ends, splice a wire at the PCM and simply pull the old wire at the control module through the dash until the new splice appears then re-splice at the wire ribbon? Sort of like fishing a heavy gauge wire through a hole by attaching to a coat hanger and thinner wire and pulling through when framing a house?

A few details would be great.

Also, can you repost the diagrams that SunlitComet posted for you? Those images are no longer available. Thanks!

So what you are saying is water is shorting the fan switch to the point of melting 3rd ac control

On mine the blower motor duct was filling with water. When the outside air temperature would drop, the fan would make a chirping, most likely from the tips of the blower motor turning through ice. The other weird thing was it would chirp if I turned left. After a large snow, it all melted, ran down into the duct, and when I turned the fan on, huge puff of electrical smoke. I replaced the blower motor, the heater control unit and harness. I then went in under the passenger side grill just outboard of the windshield wiper. There is an rectangular panel that sits just above the blower motor duct, that I siliconed and fixed the water leak. No more problems.

 

[YukonGTmaster]

Just found this in another post in Exterior, of guys with wet carpet passenger side. This is a good photo of the leaking cover panel I was talking about.

 

[tokedigital]

Ok so had my ac working nice and cold with a new ac control and 2 hours later dead again. I know about the water issue but it was a nice sunny 90 degree day no rain and boom dead again. So if anyone has any clues why it stopped powering my ac clutch from ac power button. When I jump relay it works good. So as for now I ran a switch to the relay and I got my ac back.