Heater Malfunction

zedbear · January 6, 2010

I was driving the truck today and at one point realized I was getting really hot. So I turned down the temp dial half way. A few minutes later, still blazing hot. Turned it down all the way. No go, still scorching. I turned the system off and then back on and one time got it to respond. But after turning it back up to full hot, it got stuck again.

It has manual controls and all the modes and fan speeds seem to be working fine. I'm guessing some sort of temp blend motor or solenoid has gone south. On my last vehicle, a 95 grand maquis, I always dreaded the day the temp blend door motor went bad because it would have required removing the ENTIRE dash from the firewall to access it. Luckily it never went bad. Please tell me I don't need to do that with this truck to fix it, lol. I did a little searching but didn't find anything conclusive for my truck. Thanks!

CapitalTruck · January 7, 2010

No, it's not that bad. Probably just the temperature door actuator. Do you have the dual zone climate control or only single zone?

zedbear · January 7, 2010

No, it's not that bad. Probably just the temperature door actuator. Do you have the dual zone climate control or only single zone?

Just single zone, manual controls. Is there a way to verify it is indeed the door actuator?? Thanks.

ss502gmc · January 7, 2010

From my experience it is most likely the blend actuator which is located under the hush panel to the right of the console if you have one. Pretty simple to replace compared to my mode door actuator where you have to remove most of the dash to replace!

deanp1964 · January 12, 2010

accessed my actuator today and found it to be bad - WEAK, actually. Called the "stealership" for replacement part price and was quoted $94.94. A little google-action and I located one for $40.79 at www.rockauto.com

While under my dash, I found that when stuck on HOT, if I turn off the blower, turn temp control to HOT, wait a few seconds and then turn temp control back to COLD before turning blower back on, it will allow the actuator to rotate, returning to cold position. (Its too weak to work against the force of the blown air).

This will buy me a week or so while I wait for the actuator from rockauto.com and save $55

here's another thread I found on this problem that is helpful as well: http://www.gm-trucks.com/forums/index.php?showtopic=41207

rock on.