2004 tahoe z71 with the automatic and auxiliary control rear HVAC. So I've been fighting the dreaded HVAC control module issue for awhile now.
About a year ago I noticed that the rear heat wasnt working in the rear. Popper off the body pieces and noticed the ole blend door actuator wasnt doing anything. I didnt troubleshoot the HVAC control module or the actuator I just replaced the actuator with. NEW aftermarket and replaced the Control Module with a USED one off ebay. Problem fixed. About 10-12 months later I had the same problem again. No big deal, I figured the control module was bad again, (after all it was a used part from the same year vehicle as my own.) Buy another used one from ebay, pop it in. NO DICE. I check the actuator out. I can jump it and it turns no problem but I get no voltage change on the signal wire. (Yellow) so I think my new used part is bad. I send it back and order a NEW doorman control module off amazon. It shows up and I have the same issue. I went to test the actuator again and accidently touched the signal wire and fried the new control module. So I've ordered a new part but before it gets here what else can I check? I jump the actuator to turn it to heat and unplugged it so we have heat but I really want to figure it out lol! Is there some kind of recalibration process or something I'm missing? I know one of these days I'm going to break one of these plastic clips taking this interior apart so many times!
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About a year ago I noticed that the rear heat wasnt working in the rear. Popper off the body pieces and noticed the ole blend door actuator wasnt doing anything. I didnt troubleshoot the HVAC control module or the actuator I just replaced the actuator with. NEW aftermarket and replaced the Control Module with a USED one off ebay. Problem fixed. About 10-12 months later I had the same problem again. No big deal, I figured the control module was bad again, (after all it was a used part from the same year vehicle as my own.) Buy another used one from ebay, pop it in. NO DICE. I check the actuator out. I can jump it and it turns no problem but I get no voltage change on the signal wire. (Yellow) so I think my new used part is bad. I send it back and order a NEW doorman control module off amazon. It shows up and I have the same issue. I went to test the actuator again and accidently touched the signal wire and fried the new control module. So I've ordered a new part but before it gets here what else can I check? I jump the actuator to turn it to heat and unplugged it so we have heat but I really want to figure it out lol! Is there some kind of recalibration process or something I'm missing? I know one of these days I'm going to break one of these plastic clips taking this interior apart so many times!
Sent from my SM-G950U using Tapatalk
