How to test heater controls?

[xjsc16x]

2002 Tahoe with dual zone manual controls (front on the dash and rear on the overhead). Truck was off the road for a few months, just now getting back into driving it and the heat is always blowing hot air.

Things I've done:
- confirm Air conditioning system is functional (compressor turns on, good pressure, lines going to and from the evaporator are ice cold)
- replaced blend door actuator with a new one off Rockauto
- took the actuator off and moved the rod myself and I can correctly change between cold and hot air
- relearn procedure at least 5 times now didn't do a thing

With the actuator off but still plugged in, I can see the the motor does move it a tiny bit but only maybe .5-1 degree. It's barely noticeable the amount it moves.

Is there any way I can chech the temperature contols or the signal coming to the actuator with a multimeter? What else can I do to diagnose this?

Thanks,
-Justin

 

[xjsc16x]

Bump, not sure if this is normal or not but I can turn the rod by hand when the fans are off but when they're on I have to use a pair of pliers to turn it. I assume it's because of the air blowing gives it resistance?

 

[josh336]

I came across this video the other day. It's worth a shot.


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