aright guys, let’s see if y’all can help me out. I am stumped. So I’ve been riding with out heat for a few years now due to not wanting to replace the blend doors. This year I said… it and just replaced them. They don’t work. My climate control doesn’t switch the blend door back and forth. Thought it was faulty controller so I took it out and put it in my other trailblazer, WORKS PERFECT. Took the blend door out and put it in the other one. WORKS PERFECT! So I don’t get it. I took out a light tester and tried pointing out what the issue was and I ground the light tester (obviously) and touch the wires, I can move the blend door back and forth like that. Individually touching the actual wire I can move them. But the controller itself will not move the blend door. I have tired everything and I don’t know how to fix this. The only one it moves to with the controller is the defrost. I’ve looked it up a million different ways and just the basic comes up but nothing to solve my problem. Anyone run into this?
Blend doors get no power
- Thread starter Dmartinez2296
- Start date
aaserv
Member
Not real familiar with the hvac control module but going by the wiring diag it looks like there are 2 grounds that come in to play. 1 off the module itself that appears to me to only ground the actuator circuits as the blower circuit has its own ground. There is another that comes off the recirculation actuator that should be ckd also. Im not sure which is the Recirc actuator but I do see that all the others have 5 wires going to them while this one only has 3 wires with 1 of them being the Black ground.
Looks like the main power to the module comes from Fuse 39 and is 1 of 2 brown wires going into the module. The other comes from fuse 44 and appears to feed only the blower.
It looks to me like if the compressor is running then you have to be getting power from fuse 39 so probably safe to assume that circuit is ok.
Next thing is the 5v ref circuit that feeds all the actuators EXCEPT the recir . These are the 5 wire acts . That will be the LT.Blue /Blk wire that runs from the module to all the actuators.
There is also a hot wire (Org) that I believe holds the actuator positions when the car is off but Im not sure of that. It is Fuse 36. This runs to the control module and is worth cking I guess.
The only other thing I see and I dont know how to ck it is a White wire that comes from the powertrain control module to the HVAC module. It is for serial data and appears to be used to ck the system with computer data and not in the actual operation of the system. It looks like this would feed a factory scan tool which if all else fails may be what you'll need to diagnose the problem.
Looks like the main power to the module comes from Fuse 39 and is 1 of 2 brown wires going into the module. The other comes from fuse 44 and appears to feed only the blower.
It looks to me like if the compressor is running then you have to be getting power from fuse 39 so probably safe to assume that circuit is ok.
Next thing is the 5v ref circuit that feeds all the actuators EXCEPT the recir . These are the 5 wire acts . That will be the LT.Blue /Blk wire that runs from the module to all the actuators.
There is also a hot wire (Org) that I believe holds the actuator positions when the car is off but Im not sure of that. It is Fuse 36. This runs to the control module and is worth cking I guess.
The only other thing I see and I dont know how to ck it is a White wire that comes from the powertrain control module to the HVAC module. It is for serial data and appears to be used to ck the system with computer data and not in the actual operation of the system. It looks like this would feed a factory scan tool which if all else fails may be what you'll need to diagnose the problem.