2002 GMC Envoy XL HVAC Mode Door Issues

[JonnyTahoe]

I also got a smattering of U codes.
U1000
U1026
U1041 going to clean a ground for this one.
1064
1152 May be related to the rear ac. I have the blower module removed back there.

does it look like this ?

 

[George B]

Somewhere I have a document showing how to properly re-align these things. It involves getting the little wheel that is the encoder in proper alignment with the large final drive gear

I just watched a little video on a similar one. I am going to pull that actuator and perform surgery tomorrow morning. I will measure the total resistance of the pot and then shoot for the middle. See if it likes it.

 

[George B]

I removed that module as well.View attachment 263504 does it look like this ?

No, I removed the fan control module one fried so the fan stayed on all the time. Then the replacement fried and the fan stayed on so I unplugged it.

 

[JonnyTahoe]

No, I removed the fan control module one fried so the fan stayed on all the time. Then the replacement fried and the fan stayed on so I unplugged it.

The pic I posted is the Mode Door Actuator for Tahoe and Yukon. My rear Blower kept running too good thing I was in the truck at the time. Un-plugged and removed it.

 

[George B]

The pic I posted is the Mode Door Actuator for Tahoe and Yukon's. My rear Blower kept running too good thing I was in the truck at the time. Un-plugged and removed it.

The actuator looks similar but the cam it attaches to is different.

 

[TJ Baker]

The pic I posted is the Mode Door Actuator for Tahoe and Yukon. My rear Blower kept running too good thing I was in the truck at the time. Un-plugged and removed it.

Our TrailBlazers & Envoys have similar actuators but we can replace just the actuator and not deal with that cam.

 

[TJ Baker]

I just watched a little video on a similar one. I am going to pull that actuator and perform surgery tomorrow morning. I will measure the total resistance of the pot and then shoot for the middle. See if it likes it.

Here is a picture I got from somewhere, either the TrailVoy site or the newer GMTNation site. Shows the orientation of the pertinent gears. Note the location of the printing on the small encoder gear.

 

[George B]

Crunchy!

 

[George B]

Success!
Took that actuator apart on the bench and spun the potentiometer a few times. Took the gears out of the unit and carefully plugged it into the truck. Using the Tech2 to read counts I adjusted the pot to 100 counts. Put it back together and reinstalled it. It calibrated, responded to commands and counts. If it fails again I will replace the actuator.
Now, where is that shirt...

 

[JonnyTahoe]

No, I removed the fan control module one fried so the fan stayed on all the time. Then the replacement fried and the fan stayed on so I unplugged it.

I removed mine too. Was hearing clicking in the rear every time I would turn the Ignition on was my wiper motor so I unplugged it.