Heater quit working/blowing

[iboughtatahoe23]

I think I was getting power at the connector that goes to the blower motor, which is strange because of the resistor was failing. I think it’s supposed to trip itself so it doesn’t overheat.

My old one was pretty corroded. Probably from when I left my sunroof open in a rainstorm when I first got it.

This all explains only the rear blower motor working… resistor being bad should not allow power to the blower motor to prevent fire right? Which was my case

But now that I think of it, I’m pretty sure when I tested the power to the blower motor it had like 15 V.

 

[Doubeleive]

My old one was pretty corroded. Probably from when I left my sunroof open in a rainstorm when I first got it.

This all explains only the rear blower motor working… resistor being bad should not allow power to the blower motor to prevent fire right? Which was my case

Well what it does is it drops the voltage from say 12v to 8v when you turn the fan speed down, the resistance creates heat, hence the heatsink. The old ones would get so hot the wires would melt because they didn't have any heatsink

 

[Doubeleive]

I think I was getting power at the connector that goes to the blower motor, which is strange because of the resistor was failing. I think it’s supposed to trip itself so it doesn’t overheat.

But now that I think of it, I’m pretty sure when I tested the power to the blower motor it had like 15 V.

It has whatever the battery or alternator is producing 12-15v

 

[mikez71]

for the gmt800's yes, yours is the 1st one I have seen on this forum for the gmt900's

I've heard of at least one bad gmt900 blower resistor on here before, maybe two...

 

[Doubeleive]

I've heard of at least one bad gmt900 blower resistor on here before, maybe two...

I replaced so many on the 800's I bought one for this truck years ago to have on hand just in case, that's when I discovered they were so much better made.
so I have one at the ready when the time rolls around, so far just had to replace the blower motor and 1 actuator.
I've lost a couple compressors in the past as well, I am at 180k this thing better hold up I don't have the money that crap right now.

 

[iboughtatahoe23]

Glad I was able to fix it thanks for your guys insight