Rear AC cold but front is not

[JB05Yukon]

I have already tried removing the mix door actuator from under the dash and it appears to work ok. If I remove it from the dash and leave it plugged in, and change the AC settings front, rear, driver, passenger, I can see it move through a range of about 45 degrees, total. I assume this is normal operation?

If I can't get cold AC in the front but I can in the rear, does this suggest a blocked orifice, or some other issue? Freon levels and pressure are good.

Thanks!

 

[Doubeleive]

I have already tried removing the mix door actuator from under the dash and it appears to work ok. If I remove it from the dash and leave it plugged in, and change the AC settings front, rear, driver, passenger, I can see it move through a range of about 45 degrees, total. I assume this is normal operation?

If I can't get cold AC in the front but I can in the rear, does this suggest a blocked orifice, or some other issue? Freon levels and pressure are good.

Thanks!

you might be looking at the wrong actuator, the blend door actuator should only move when commanding hot or cold that is it's sole function. if the one you are looking at is changing when you select up or down or left or right then it's the wrong one for sure.

 

[JB05Yukon]

you might be looking at the wrong actuator, the blend door actuator should only move when commanding hot or cold that is it's sole function. if the one you are looking at is changing when you select up or down or left or right then it's the wrong one for sure.

Thanks for the reply doubelieve. Do you know of the location of any others? I should perhaps clarify as well that I was seeing movement by alternating between calls for max heat or max cold, across the locations. I just wanted to check it was moving at all to try and rule it out.

After being in the car again yesterday, with the actuator out and hanging by its harness, the front is set to 60 degrees, minimum fan, and is passing hot air, whilst the rear is set to 66 degrees and blows nice and cold. I'm feeling confident that this rules out the compressor.

 

[Doubeleive]

Thanks for the reply doubelieve. Do you know of the location of any others? I should perhaps clarify as well that I was seeing movement by alternating between calls for max heat or max cold, across the locations. I just wanted to check it was moving at all to try and rule it out.

After being in the car again yesterday, with the actuator out and hanging by its harness, the front is set to 60 degrees, minimum fan, and is passing hot air, whilst the rear is set to 66 degrees and blows nice and cold. I'm feeling confident that this rules out the compressor.

I haven't dug into the front of one in a while but the blend door should be the one closest to the heater core, you can take the actuator off and manually turn the door with a tool and then feel the vents

 

[JB05Yukon]

I haven't dug into the front of one in a while but the blend door should be the one closest to the heater core, you can take the actuator off and manually turn the door with a tool and then feel the vents

That’s exactly what I’ve done so far. Moving it manually I have hot up front and cold In the back. Plugged in I get ambient/cold

 

[JB05Yukon]

That’s exactly what I’ve done so far. Moving it manually I have hot up front and cold In the back. Plugged in I get ambient/cold

 

[Doubeleive]

That’s exactly what I’ve done so far. Moving it manually I have hot up front and cold In the back. Plugged in I get ambient/cold

?? the rear has a separate control in the rear passenger kick panel, the doors in the dash do not control the rear air in any way. if the rear is working properly just turn it off, you want to concentrate on the front

 

[natrotciv]

There was a post about taking the actuator apart and wiping the old grease out and regreasing the gears. Also check to see if the grease is smeared on the chip/module inside and clean if necessary. I did this with mine and it saved me quite a bit of money and got my front AC working again