2001 GMC Sierra 1500 SLT (Extended Cab) 5.3L v8 - Troubleshooting HVAC issues
Hi Scotty,
Been a long time fan watching your youtube videos for years. Have asked periodically with issues I've come across with my truck. I have a 2001 GMC Sierra 1500 SLT (Extended Cab) 5.3l v8 4wd with 260k miles on it. The newest one thus far is about 2 weeks ago my HVAC system in the truck no longer blows hot air whatsoever and no defrost. I have taken the kick panel out from under the dash. Thus far tested the temperature actuator by changing the temperature. The actuator moves freely with no issues and the blend door as well with no binding. I have replaced the cabin air filters and vacuum out any debris that may of still been in there before I bought the truck, years ago.
I have tested the actuator under the driver-side, near the steering column by turning the vent locations dial and defrost. No binding involved, and the actuator moves freely as well.
I have checked the blower motor and that works.
I have checked my heater core and the lines under the hood and nothing is leaking and both lines are hot, as they should.
I have attempted to do the HVAC relay / fuse reset / recalibration with no luck.
I am at a lost of what it might be is all. I still get heat in the cabin of the truck when the blower motor is turned off, after the engine has reached optimal temperature, but as soon as I turn it on, the air temperature (regardless of where it is set on the temperature dial) will turn cold immediately.
I am trying to do the work myself so I do not have to take it to a shop where I know they will charge me well over $1k just to take the dash apart just to find the problem and possibly have a solution.
Any insight and suggestions will be much appreciated and keep up with the good work on your videos.
Wish you the best on your new adventures in Tennessee.
XLEMUR
You might want to try replacing the instrument panel. Scotty's mentioned times where he's seen the same thing and weird AC/Heat gremlins where the blower knob or something was causing it. This is honestly not my particular strength but if its not a button thing a smoke machine might help. Take the smoke machine and run the heat and see if it will blow the smoke through. This is so you don't have to take apart the whole dash. If it blows smoke through and you know the heater core is working idk what else to check since I haven't worked on alot of issues like this myself. GL with mystery always cold gremlin.
