Problem with A/C on drivers side

[AllTerrainSierra]

So today its 86 degs out and I turn on the a/c. I push the auto button and it seems to be working fine then about approx 30-45 mins later i feel heat. Its only from the drivers side the pass side is ice cold. I put my hand over the vent and its super hot air. I adjust the temp all the way to 90 then back to 60 nothing happens. So i shut it off and turn it back on and its still doing the same thing. I play around with it again and finally give up and turn it off and roll the windows down. I get to my destination and a couple hours later I get back in the truck to leave turn on the a/c and it seems to be working intill about maybe 30 mins and it turns hot again. I shut it off again intill I arrive home then shut the truck off and restart it and it works. So it seems that when I turn the engine off and restart it works again. I think it might be the valve/door that changes from heat to a/c or maybe some electronic module? Anyone have the same problem? Fix? Thanks in advance!

 

 

Rob.

[txab]

Usually requires the replacement of the malfunctioning actuator. I wouldn't hold out too much hope that this will work, but

you might try a re-calibration.

 

Try disconnecting the battery for
a few minutes. Reconnect it. Or remove the HVAC/ECAS fuse for a minimum of 10 seconds.

Re-install the HVAC/ECAS fuse.

 

Then turn the key to the on position, but
don't start. Don't touch the HVAC controls. Let them do whatever that
want to do. Air flow may change outlet points during this time. Wait
about 1 minute. Turn key off. Sometimes opening and closing the door can
make a difference as the vehicle controls see this as "cycle"
completion. Next start the vehicle and drive it a short distance and see
how it performs.

 

You may indeed need to replace an actuator.

[AllTerrainSierra]

Usually requires the replacement of the malfunctioning actuator. I wouldn't hold out too much hope that this will work, but

you might try a re-calibration.

 

Try disconnecting the battery for

a few minutes. Reconnect it. Or remove the HVAC/ECAS fuse for a minimum of 10 seconds.

Re-install the HVAC/ECAS fuse.

 

Then turn the key to the on position, but

don't start. Don't touch the HVAC controls. Let them do whatever that

want to do. Air flow may change outlet points during this time. Wait

about 1 minute. Turn key off. Sometimes opening and closing the door can

make a difference as the vehicle controls see this as "cycle"

completion. Next start the vehicle and drive it a short distance and see

how it performs.

 

You may indeed need to replace an actuator.

Thanks Txab. Are there any instructions on how to change the actuator if indeed that is the problem? I read that the driver side is the easier one to do. Thank you.

Rob.

[sromagnoli]

been dealing with the same thing. the Left side air temp actuator is actually easy to get to. to get to it, on the passenger side from underneath the dash remove the cover over the blower motor - it has 3 screws. also remove the knee bolster panel - it just pulls out. this will reveal an actuator that is bolted under the HVAC unit near the center hump. if you look at it with a flashlight while the vehicle is running, put the AC in auto mode and click the driver side temp up and down you will see (should see) the center of the actuator rotate moving the blend door inside the HVAC unit. there is a small notch in it so you can see which way it is turned. the notch lines up with little lines that are part of the plastic housing. when the notch is all the way towards the drivers side it is full cool on the driver side. notch towards the passenger side is full warm on driver side. the actuator can be removed by just removing the electric plug (vehichle and ignition off) then remove the 2 screws - it then drops straight down. from there you can check and see if the door rotates freely. I actually took my actuator apart (it is just held together by plastic clips), removed the white plastic gear, removed the black acutator gear/sweeper and slightly bent the copper sweeper so it contacts the copper slide better (this is the potentiometer that actually tells the BCM where the actuator is at). upon reinstallation i followed the recalibration procedure mentioned in this thread and it seems to be working fine now. before i did this it appeared to move erratically and didnt go all the way to the cool side, now it appears to move more positively and moves all they way from cool to warm. good luck with yours.

[AllTerrainSierra]

been dealing with the same thing. the Left side air temp actuator is actually easy to get to. to get to it, on the passenger side from underneath the dash remove the cover over the blower motor - it has 3 screws. also remove the knee bolster panel - it just pulls out. this will reveal an actuator that is bolted under the HVAC unit near the center hump. if you look at it with a flashlight while the vehicle is running, put the AC in auto mode and click the driver side temp up and down you will see (should see) the center of the actuator rotate moving the blend door inside the HVAC unit. there is a small notch in it so you can see which way it is turned. the notch lines up with little lines that are part of the plastic housing. when the notch is all the way towards the drivers side it is full cool on the driver side. notch towards the passenger side is full warm on driver side. the actuator can be removed by just removing the electric plug (vehichle and ignition off) then remove the 2 screws - it then drops straight down. from there you can check and see if the door rotates freely. I actually took my actuator apart (it is just held together by plastic clips), removed the white plastic gear, removed the black acutator gear/sweeper and slightly bent the copper sweeper so it contacts the copper slide better (this is the potentiometer that actually tells the BCM where the actuator is at). upon reinstallation i followed the recalibration procedure mentioned in this thread and it seems to be working fine now. before i did this it appeared to move erratically and didnt go all the way to the cool side, now it appears to move more positively and moves all they way from cool to warm. good luck with yours.

Thank you Scott for the detailed instructions.

 

 

Rob