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Discussion Starter · #1 ·
I had this happen once and nothing I did would get the heat to come on and it was cold outside. I ended up turning truck off then back on and it worked. Anyone knows what causes this?

Thanks
 

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I had the same problem. Everything I have read points to the GEM module. It's supposed to be attached to the back of the fuse box, but I have heard a few say theirs wasn't. Sometimes there is a small leak in the windshield area that drips onto the box and the insides get corroded. Other times it just craps out I guess. Mine looked just fine inside so I merely cleaned up the contacts and put it back together. No problems since. (knock on wood)
 

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Discussion Starter · #3 ·
I did a search and most say it's the automatic light relay. If you turn the lights from auto to off then back to on or auto it resets the relays and the HVAC lights come back on. I should have done the search before I posted I didn't know it was a common problem. Thanks
 

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I did a search and most say it's the automatic light relay. If you turn the lights from auto to off then back to on or auto it resets the relays and the HVAC lights come back on. I should have done the search before I posted I didn't know it was a common problem. Thanks
Ditto. Mine's done it for years, about once every 6 months or so. I remember reading it was the relay also, it just needs a little smack on the head. :D
 
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