weird A/C glitch for '05 Silverado

pmoorse · September 7, 2005

this has only happened to me twice, but when it does it's a real pain. the A/C will be cranking out cold like it's supposed to, then without any changes in the control settings it starts putting out really hot air. the only way to get it to stop temporarily is to turn the ventilation system off until i can get to a place to stop and turn the truck off and back on, then magically it works fine again.

has this happened to anybody else, and if so, is there an easier way to correct the problem? fortunately for me both times i was driving around town so pulling off the road wasn't too big a deal

Bish · September 7, 2005

this has only happened to me twice, but when it does it's a real pain. the A/C will be cranking out cold like it's supposed to, then without any changes in the control settings it starts putting out really hot air. the only way to get it to stop temporarily is to turn the ventilation system off until i can get to a place to stop and turn the truck off and back on, then magically it works fine again.

has this happened to anybody else, and if so, is there an easier way to correct the problem? fortunately for me both times i was driving around town so pulling off the road wasn't too big a deal

<{POST_SNAPBACK}>

Not exactly the same symptom but I have a similar problem and it may be the same culprit.

If I turn the heat on, it will stay on MAX heat until I shut it off. It never goes to hot by utself. I am told this is the device that controls the air mix door and replacing it will solve the problem. Don't know if it is an electric or vacuum module.

Mouse2 · September 7, 2005

Check and see if it is just one side of the cab or both the next time it happens. If it is one side only, it could be the air door servo motor or a controller head issue. The way to know for sure is to plug in an analyser into the service port and read the door position in relation to the controller head desired position. This may be hard if this is an intermittant problem.

Good Luck...

kdm101 · September 8, 2005

I've had a similar event happen once so far. However, it was during fall and it would only pump out AC! All of the lights were on too - fresh air, recirc, and AC, and they wouldn't turn off. Same solution though - shut down and it reset itself. Since the climate module in the dash had nearly all of the back lights burned out anyway, I went out to Ebay and picked up a new unit. So far, I haven't had any recurrence, but I have no way of knowing whether it was the climate module or merely a momentary glitch in the BCM (body control module). It worked fine after that for a few more months before I did the replacement.

Meanwhile, I have yet to get around to replacing the bulbs in the original unit. I also wanted to replace the dull yellow LEDs with something more cool (such as a blue LED for the AC button!).

Markeaux · September 8, 2005

I too had the lockup on full heat. Fix was:

52474810 temperature valve bottom actuator

... drop the hush panel to get to it on passenger side.

Black Bart · September 11, 2005

I dont know how many of you this will help, but, I just

helped a friend with a problem like this(turn the heater

on and when it is warm you cant control the temp).

It turned out to be the door actuator motor gearbox,

one of the plastic gears was not moving freely and

when it was hot it would hardly move.

We removed the gear and with a drill bit a little larger

than the hole just twisted it by hand, put a little lube

on it and has been working fine since.

Black Bart

lrymal · September 11, 2005

...has this happened to anybody else, and if so, is there an easier way to correct the problem? fortunately for me both times i was driving around town so pulling off the road wasn't too big a deal

<{POST_SNAPBACK}>

STOP! Don't do any modifications or attempts to fix this. You have a NEW truck. It is under warranty. Don't try to fix it. Take it in and let the dealer work with this, otherwise, your attempts may void the warranty and you'd have to pay for the repair.

budhayes3 · September 11, 2005

...has this happened to anybody else, and if so, is there an easier way to correct the problem? fortunately for me both times i was driving around town so pulling off the road wasn't too big a deal

<{POST_SNAPBACK}>

STOP! Don't do any modifications or attempts to fix this. You have a NEW truck. It is under warranty. Don't try to fix it. Take it in and let the dealer work with this, otherwise, your attempts may void the warranty and you'd have to pay for the repair.

<{POST_SNAPBACK}>

Absolutely!!

pmoorse · September 11, 2005

STOP! Don't do any modifications or attempts to fix this. You have a NEW truck. It is under warranty. Don't try to fix it. Take it in and let the dealer work with this, otherwise, your attempts may void the warranty and you'd have to pay for the repair.

<{POST_SNAPBACK}>

don't worry, i have no desire to take anything apart when i have my warranty . i'm planning on taking it in some time in the next week or so, i'll see what they tell me

i guess when i asked for easier fixes for this, i meant short-term fixes that don't involve pulling over and shutting the engine off.

MemphisDoug · September 12, 2005

STOP! Don't do any modifications or attempts to fix this. You have a NEW truck. It is under warranty. Don't try to fix it. Take it in and let the dealer work with this, otherwise, your attempts may void the warranty and you'd have to pay for the repair.

<{POST_SNAPBACK}>

don't worry, i have no desire to take anything apart when i have my warranty . i'm planning on taking it in some time in the next week or so, i'll see what they tell me

i guess when i asked for easier fixes for this, i meant short-term fixes that don't involve pulling over and shutting the engine off.

<{POST_SNAPBACK}>

When I have the heat selector in my truck set for the floor I have very little control of the temperature. It wants to be very hot all the time. I have found that if I keep the selector just a tad bit in the direction of the dash vents, I can control the heat. I don't know why that makes a difference but at least it keeps me from being too hot.

SierraCrewGuy · September 13, 2005

I have an '05 Crew Cab 2wd and have had this problem once. My son turned the knob to hot by mistake and when I turned it back, only hot air came out. I turned it back to cold and it didn't care. When I turned the truck off and back on, it worked fine. No further problems thus far. The next time, I'll take it in for repair.