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97 Tahoe LT HVAC switch repeated failures

A100

By A100
in Ask A GM Technician

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A100 New Member

A100

Posted
Posted

Hi

 

 

My first post here... & of course it's because I need help :cheers: Thanks in advance for anyone who might have some insight on this.

 

 

I've had my 97 Tahoe since new. Sometime around 2001 the HVAC switch panel failed. I replaced the entire panel (GM part number 09378805) on a whim & all was working again. I intended to research the problem some more but forgot about it as all was fine for quite awhile. Fast foward to last summer the same thing happened again so I stuck another panel in there & it worked. When I removed it I noticed this time the plug that goes to the blower speed switch suffered some heat damage. I checked the old one I removed & sure enough it had the same damage but less obvious. Realizing this was probably going to fail again I ordered another panel to keep as a spare & decided until I figure this out I would not use the highest blower speed setting thinking it would be less likely to fail. Well a few weeks ago it failed again & the newest replacement only lasted a week or two. I think I had accidentially had the blower on the highest setting.

 

These all seem to have the same problem.. the plug over heating & melting. I'm guessing that there is something wrong with the vehicle wiring causing this. PErhaps an intermittant short or something but back tracking the harness I do not find anything obvious. There have never been any blown fuses during any of these failures.

 

Has anyone else here experienced the same type of problem & figured out what the cause is? I'd be very grateful for anyone who could hewlp on this issue.

 

Thanks!

Joe

Nash Enthusiast

Nash

Posted
Posted

Check your fuses and make sure they are the correct rating (ie 20 amp instead of 10 amp).

Mr. Smith Enthusiast

Mr. Smith

Posted
Posted
Hi

 

 

My first post here... & of course it's because I need help  :cheers:  Thanks in advance for anyone who might have some insight on this.

 

 

  I've had my 97 Tahoe since new.  Sometime around 2001 the HVAC switch panel  failed.    I replaced the entire panel (GM part number 09378805) on a whim & all was working again.  I intended to research the problem some more but forgot about it as all was fine for quite awhile.  Fast foward to last summer the same thing happened again so I stuck another panel in there & it worked. When I removed it I noticed this time the plug that goes to the blower speed switch suffered some heat damage.  I checked the old one I removed & sure enough it had the same damage but less obvious.  Realizing this was probably going to fail again I ordered another panel to keep as a spare & decided until I figure this out I would not use the highest blower speed setting thinking it would be less likely to fail.  Well a few weeks ago it failed again & the newest replacement only lasted a week or two.  I think I had accidentially had the blower on the highest setting. 

 

  These all seem to have the same problem.. the plug over heating & melting. I'm guessing that there is something wrong with the vehicle wiring causing this.  PErhaps an intermittant short or something but back tracking the harness I do not find anything obvious.  There have never been any blown fuses during any of these failures.

 

Has anyone else here experienced the same type of problem & figured out what the cause is?  I'd be very grateful for anyone who could hewlp on this issue. 

 

  Thanks!

    Joe

 

 

 

 

High resistance usually causes what you describe here. As it causes heat to build up damaging the connector and in extreme cases fire. Check the circuts for high resistances.

ChevyTech007 Enthusiast

ChevyTech007

Posted
Posted

If you have not replaced the connector that plugs into the control head, that is your problem. The terminals in the connector are what caused it to burn in the first place. The terminals do not have enough tension to make a good tight fit on the pins in the control head. That builds up heat and causes the control head and connector to melt. You need to get a new control head and a connector. Splice the new connector into the harness and you problem will be solved. I have seen it many times.

A100 New Member

A100

Posted
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Posted

Thank you for the help !!

 

 

I will try to track down another plug today... At this poiont I dont really have a choice anyway as it melted pretty goot this last time.

 

 

Hopefully I'll be able to crank up the AC in the next few days!

 

 

Joe

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