A/C issue

[03GMCYukonXL]

So I have a 2004 Tahoe, and the previous owner before me had a strange valve handle on one of the lines going into the vehicle. If you turned it off and prevented the hot water from going into the heater core the AC would blow cold, if you turned it on it would always blow warm air. The actuator was making a funny noise as well so I replaced it. The one in the lower footwell. I also replaced the hose with one that hasn't been cut and have a valve handle put on it. I have tried resetting my HVAC system by following the ride up on this site by unplugging the fuse, and it still just blowing lukewarm air. Should I replace the other actuator up behind the airbag? I'm not sure which actuator controls the hot to cold blend. Any help would be greatly appreciated

 

[03GMCYukonXL]

So I have a 2004 Tahoe, and the previous owner before me had a strange valve handle on one of the lines going into the vehicle. If you turned it off and prevented the hot water from going into the heater core the AC would blow cold, if you turned it on it would always blow warm air. The actuator was making a funny noise as well so I replaced it. The one in the lower footwell. I also replaced the hose with one that hasn't been cut and have a valve handle put on it. I have tried resetting my HVAC system by following the ride up on this site by unplugging the fuse, and it still just blowing lukewarm air. Should I replace the other actuator up behind the airbag? I'm not sure which actuator controls the hot to cold blend. Any help would be greatly appreciated

 

[swathdiver]

So I have a 2004 Tahoe, and the previous owner before me had a strange valve handle on one of the lines going into the vehicle. If you turned it off and prevented the hot water from going into the heater core the AC would blow cold, if you turned it on it would always blow warm air. The actuator was making a funny noise as well so I replaced it. The one in the lower footwell. I also replaced the hose with one that hasn't been cut and have a valve handle put on it. I have tried resetting my HVAC system by following the ride up on this site by unplugging the fuse, and it still just blowing lukewarm air. Should I replace the other actuator up behind the airbag? I'm not sure which actuator controls the hot to cold blend. Any help would be greatly appreciated

The one you changed was for the driver's side. The other is for the passenger side. Next to it is the one for fresh air and in the driver's footwell is the mode actuator.

Having said that, if you are getting warm air on both sides no matter what, then I would suspect the controller. If you have the Suburban or Yukon in your signature still, swap one out and see if the AC starts working normal again.

The best way to know is to put a scan tool on it and pull the internal BCM codes. IPhones with the CarScanner app can see them too.

 

[03GMCYukonXL]

The one you changed was for the driver's side. The other is for the passenger side. Next to it is the one for fresh air and in the driver's footwell is the mode actuator.

Having said that, if you are getting warm air on both sides no matter what, then I would suspect the controller. If you have the Suburban or Yukon in your signature still, swap one out and see if the AC starts working normal again.

The best way to know is to put a scan tool on it and pull the internal BCM codes. IPhones with the CarScanner app can see them too.

The thing is, is it was working with the lever switched and then I changed the actuator and hose and now it doesn't do anything but warm air on both sides. Perhaps both actuators were bad and the one I just replaced was bad from the factory?

 

[03GMCYukonXL]

OK so I took the actuator out and could see no movement at all. However, I manually flipped the blend door and still get nothing but hot air. If I block the heater core off with a valve, I get cold air. What can this possibly be?

 

[swathdiver]

OK so I took the actuator out and could see no movement at all. However, I manually flipped the blend door and still get nothing but hot air. If I block the heater core off with a valve, I get cold air. What can this possibly be?

i'm not 100% sure. I do know that the new actuators ought to be calibrated. There is a manual way to do this on the GMT800s that many say works. I have GMT900s and the manual way has never worked for me, I have to use my Tech-2 each time.

The wrong actuator can make the system work the opposite, cold instead of hot and hot instead of cold.

Do the modes work alright? Heater, defrost, mid, etc.?

@91RS @Scottydoggs @rockola1971 @Bill 1960 @Sam Harris

 

[03GMCYukonXL]

Yes the modes work OK. There was this one time that turning the fan speed all the way up seemed to out it on floor mode but other than that it's fine. The actuator doesn't nice but I manually flipped the door. What is the manual way to reset? I've done the fuse removal way about 10 times lol.

 

[swathdiver]

Yes the modes work OK. There was this one time that turning the fan speed all the way up seemed to out it on floor mode but other than that it's fine. The actuator doesn't nice but I manually flipped the door. What is the manual way to reset? I've done the fuse removal way about 10 times lol.

I don't remember for those. @rdezs @OR VietVet

 

[rdezs]

Not sure how to do it manually. I use a Tech 2...

 

[OR VietVet]

Not sure how to do it manually. I use a Tech 2...

What @rdezs said.

 

[03GMCYukonXL]

Ac compressor isn't engaging. It was engaging fine until I changed the actuator and tried to recalibrate. I'm starting to think it's a coincidence and the climate module is fried. It already does the wierd thing with the temp when I turn the knob. I'm going to test the clutch by putting power to it before anything else

 

[rockola1971]

Check your pressures. If low then clutch will not engage because the low pressure cutoff switch will not let it.