Climate control problems after battery change

Discussion in 'GM Electrical Tech' started by ptdavisjr, Jun 19, 2009.

  1. ptdavisjr

    ptdavisjr New Member

    I am sure some (or all) have heard of this problem, but I need some help because its driving me nuts! I installed a new battery in my wifes 2002 Chevy Tahoe. Immediately afterward, the controls would only blow heat through the defrost setting, no matter what the dial was set to. Also, when I tried the AC the light on the button would just blink and never turn the AC on. Its a real pain in the butt that this happened just from a battery swap!!!
  2. Jimmiee

    Jimmiee New Member

    I've never heard of that problem. Did you clean the battery cables with a battery terminal tool? Did you hook up the battery with the key in the on position?

    Try disconnecting the battery for 5 minutes and see what happens.
  3. bry2500

    bry2500 New Member

    Can't say this happened to me but something similar with the wife's Toyota Sienna. I changed the battery and then my auto window down/up didn't work. It would work manually but not automatically. After 3 days it started working again. Don't know why but I figure it had to go through somekind of reset cycle.

    I know that Toyota and GM are two completely different animals but alot of electronics function similarly. This may be your issue.

    How long has it been since you replaced the battery?
  4. F E Knucklebuster

    F E Knucklebuster New Member

    Had this happen to me yesterday with a radio swap. It blew only hot air on the passenger side. While at the dealer having the radio programmed I mentioned the problem to them and they said often an off/on with the key will reset things. It worked with me. Mine's working fine now.
  5. ptdavisjr

    ptdavisjr New Member

    It has been quite awhile now. We have just lived with it until we could find an answer. I will try to disconnect for 5 minutes and then reconnect and see if that works.
  6. ptdavisjr

    ptdavisjr New Member


    do you mean an off/on with the key while swapping the battery? I disconnected the battery for ~5 minutes and tried again, no luck. anybody else have any ideas? this is crazy that all this could happen from a battery swap! I still can't believe it!!!:grrrrrr:
  7. F E Knucklebuster

    F E Knucklebuster New Member

    Here was my understanding.

    When the battery is disconnected the actuators controlling the climate control can lose their position. They think they are in the cold position when they are really in the hot. Disconnecting the battery again won't correct it - it's an on/off thing with the key. You may have to experiment - ie - off/on without cranking, off/on without cranking 3 times, off/on with cranking. Mine did it with a simple off/on with cranking.
  8. ptdavisjr

    ptdavisjr New Member


    Sorry for the idiocy, but when you say "on/off with cranking" do you mean just normal starting of the vehicle? does the dial on the heater need to be set to hot when doing this? I have been driving with this problem since winter, so normal starting hasn't changed anything. I will try your other two suggestions though.
  9. F E Knucklebuster

    F E Knucklebuster New Member

    Right - but with a delay at each step.

    I'm just learning how all of this new computer controlled stuff works - most of it beyond me. I sounds like the actuator that controls the hot/cold on that side is either stuck or shot. I don't think I'm being much help here especially when I venture out into the opinion venue.

    That being said, I found a couple of things online for you to try. Make sure you let us know if one works.

    1
    I might have a solution for some of you that had the climate control fail to defrost mode only, after I replaced the battery. I tried several things that I read about on different forums and while I was playing under my dash I bumped my Power Seat switch. To reset the seat position, I pushed my Driver preference button and my Climate Control defaulted to my old setting and is now working.


    2
    Pulled the hvac/ecas fuse and left it out for 1 minute. reinstalled the fuse and started the vehicle with the ac off. Turned the ac on and it made some motor noises (im sure it was the motors resetting on the actuators) within 30 sec cold air from both sides
    Last edited: Jun 25, 2009
  10. Ive experianced my a/c blowing hot air after battery disconnect. Turned key off and on a few times and this cleared things up.
  11. ptdavisjr

    ptdavisjr New Member

    I'm gonna try all of these suggestions, and if any of them work I will definitely post the results!!! I don't want anybody else to have to go through this!!!!:grrrrrr:
  12. cdenny

    cdenny New Member

    Read all the sites on AC /Hot/Cold...

    After several months of hot air blowing on the drivers side and cold on the passenger side and trying ALL the great tips (none of which worked) I got it. Start the truck "2005 Z71" and hit the #1 seat positioning setting on the door. BOOM! Cold air on both sides. Then I just set the seat back to the way I like it. It about crushed me into the steering wheel.

    I will let you all know how long it stays :party:...Denny
  13. ptdavisjr

    ptdavisjr New Member

    i will try that also, damn! why does getting the heat/ac to work have to be like figuring out a rubic's cube!!?? I feel like in order to figure this out I am going to need MacGyver, or the Nicholas Cage character from National Treasure to figure this out!!!! "press here, tap foot twice, turn key, jump on one foot..........:lol:
  14. ptdavisjr

    ptdavisjr New Member

    just a heads up, I haven't got to try any of the suggestions yet, since my wife has been driving the Tahoe!!! But today's the day! I wll let you know what (if anything) works!!:great:
  15. ptdavisjr

    ptdavisjr New Member

    ok, just finished trying all of the suggestions on this thread, and nothing. I tried the on/off with cranking, on/off without cranking, on/off without cranking 3 times, pulling the hvac fuse for one minute, pressing the #1 seat memory setting.....nada. The a/c does work but the dial has to be on the dash setting even though it doesn't blow from the dash only the defrost setting, and still no heat on the rear climate control. I have just about had it with this thing! it seems everybody else has a solution to the EXACT same problem, but none of those solutions have worked for me!!!:grrrrrr::grrrrrr: If anybody has ANY other suggestions, I would be happy to try them.
  16. Jimmiee

    Jimmiee New Member

    You may have a problem in the HVAC control module. Have you checked it for codes?
  17. ptdavisjr

    ptdavisjr New Member


    no I haven't. do I need to take it to the dealer to do this? Also, I turned on the tahoe and watched the actuator (I think that's what its called) just above the accelerator pedal behind the dash. The black plastic part seemed to want to move when the dial was adjusted but wouldn't. So I pushed on it a little to "help" it and it changed to the floor. Does this mean that the actuator is shot? Seems stupid that it would go simply because I removed the battery!! but what do I know......
  18. Jimmiee

    Jimmiee New Member

    Before you start changing parts get the body control module scanned. Any good scanner that repair shops use can retreive the codes. Many code readers will not see anything but Generic codes so make sure you use a good scanner.
  19. ptdavisjr

    ptdavisjr New Member

    I will have to find that darn warranty that I bought!!! :oops:
  20. chevylurker

    chevylurker New Member

    Hey all, I'm new tothis forum, but I have had the same problem as ptdaivsjr in my '03 Silverado. I have swapped out the control panel and the (modulator?) realay switch? under the dash. Popped and checked all teh fuses and tried the other tricks as well. No joy. I haven't heard about scanning the modualtor until now. Would I have to go the stealership to get this done?
    I'll let you knwo if I find another solution.

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