So my quarantine project was replacing the heater core, AC evap, blower motor, and blend door actuator on my 2001 Cherokee. HUGE pain in the *** but I got it done, and everything went back together as expected. I also replaced the Passenger Door Module while I was at it.

When I reconnected the battery, there was a constant clicking from a relay at the fuse panel, and the power controls for the driver's seat didn't work. Weird, but I figured I'd see if it would start all the same. When I started it, smoke started coming from the vents with a minute or so! Yikes!!

I'm about to pull the the dash back off tomorrow to try to figure out what happened, but thought I'd ask here to see if anyone has any ideas.

Thanks!

 

Did it smell like burning wires? Sounds like maybe pinched a wire and got a short maybe?

 

Not sure. Smelled like plastic is involved.

 

When you reinstalled the dash, the bolts on each end are a ground for that system. Some people have had issues not getting a proper ground after replacing heater core assembly and bolting the dash assembly back up to the sidewalls. Check to make sure those are bolted well and you have good body ground. Just another thought, but if you are smelling burning plastic, may be another issue. I would still check it.

 

In my experience, a burnt plastic smell means there was a short in the wiring. Grab a flashlight and look up into the dash and check the wiring and connections. Or, take the dash back out and check the wiring and connections. Taking the dash out will give full access to anything back there, and, if theres an issue, it will be easier to fix.

 

So after after exhausting all other ideas as to what could have gone wrong, I sucked it up and pulled the HVAC box again. The brand new blower motor is completely burnt out. Any ideas why that might have happened?

 

Could of been a bad motor.