Heater blowing smoke

[SarahsGMC]

Friend made the mistake of tacking some welds on the truck without unhooking battery a few hours later we crankd the heat and smoke was rolling out of passenger footwell. Now the fans won't go off unless I unhook battery. Any idea on what happened? I'm convinced it has something to do with welding but not sure.

[SarahsGMC]

To the bar we were making only reason I say that is because the guys that did my bros exhaust fried my brothers o2 sensors but I did some research and found the 03-06 heaters wiring harnesses are being recalled..

[GasHog369]

It is a very common issue. The fix for it will depend on if he has the auto climate control or manual1-5 fan speed .

 

Auto = buy the part on amazon and do it himself

 

Manual= take truck to dealer, they will grandfather him in and do the repair for free.

 

I'll try and find my post from back in the day.

[SarahsGMC]

It's my truck I'm thinking ill need a new wiring harness for the heater?

[Doug_Scott]

You will find the resistor block that controls fan speed has burnt out, and it may have taken the plug out as well. You will likely only need the resistor block itself, and the connector that plugs into it. I would think that GM or some aftermarket company will have a repair kit to replace those two parts. It is very common issue.

[SarahsGMC]

Yea we tore it apart today and found out its real common I have the relay just need to get the plug