Hi, all--need some advice on a persistent HVAC issue. Have been through a bunch of threads here and elsewhere and I can't seem to figure out what's going wrong here.
I have a 2004 Yukon XL, SLT, 2WD. About 270K on the motor, lots of upgrades/changes over the last seven years and 130K of cross-country road trips, daily driving, and family jaunts hither and yon, but the HVAC is insisting on giving me a little bit of a runaround.
To sum, my wife's biggest complaint about the truck (outside of the noise the aftermarket dual 16" e-fans make), is that the front Auto-Temp HVAC has been sketchy for the past couple of years. Early problems related to the pass side front blowing hot air when the rest of the car is blowing cold, or the system just getting overloaded in the summer and giving up the ghost. In the last year or so we've replaced juuuust about every part of the system, outside of the evaporators, and while it seems like we've cured some of the problems, each cure seems to bring up another issue, and we're still struggling with it. We've done the blend actuators, compressor, orifices, condenser, A/C head, resistor, blower motor, and retrofitted a cabin air filter while we were at it. All new parts from reputable companies.
Current issue is that, after the A/C motor seemed to go out (original unit), I did another blower motor resistor change when I swapped the motor. We got about a week of usage and the fan stopped working again--tried the A/C reset procedure, no dice. I swapped in a spare AC head controller, which did nothing positive, but now the T/C dashboard idiot light activates at start. That seems to be related to something malfunctioning in the head controller, but no idea why, and I'm going to put my old OEM one back in, and relegate the "new" one back to spare parts. I have a new resistor on the way, so I'll swap that in and see if it was just a bad resistor. The motor I installed initially was bad, so it may have weakened the one that's in now. Engine compartment fuses (10A and 40A) are both good.
My question at this point is "Am I missing something?" Is there some other part of this system that I've overlooked here? The rear A/C works GREAT--no issues, blows super cold, etc. Rear controls are predictable and effective. The front controller, fan, and resistor just never seem to want to work together, even when all of the parts are new and "working", there are weird behaviors--for instance, the inability to activate recirculation, but only sometimes. The system goes in and out of Auto mode, and there are other bits of oddness that seem to come from the A/C controller, but not consistently, and swapping in a new head didn't seem to solve those problems. Is there something else I should be looking at?
I have a 2004 Yukon XL, SLT, 2WD. About 270K on the motor, lots of upgrades/changes over the last seven years and 130K of cross-country road trips, daily driving, and family jaunts hither and yon, but the HVAC is insisting on giving me a little bit of a runaround.
To sum, my wife's biggest complaint about the truck (outside of the noise the aftermarket dual 16" e-fans make), is that the front Auto-Temp HVAC has been sketchy for the past couple of years. Early problems related to the pass side front blowing hot air when the rest of the car is blowing cold, or the system just getting overloaded in the summer and giving up the ghost. In the last year or so we've replaced juuuust about every part of the system, outside of the evaporators, and while it seems like we've cured some of the problems, each cure seems to bring up another issue, and we're still struggling with it. We've done the blend actuators, compressor, orifices, condenser, A/C head, resistor, blower motor, and retrofitted a cabin air filter while we were at it. All new parts from reputable companies.
Current issue is that, after the A/C motor seemed to go out (original unit), I did another blower motor resistor change when I swapped the motor. We got about a week of usage and the fan stopped working again--tried the A/C reset procedure, no dice. I swapped in a spare AC head controller, which did nothing positive, but now the T/C dashboard idiot light activates at start. That seems to be related to something malfunctioning in the head controller, but no idea why, and I'm going to put my old OEM one back in, and relegate the "new" one back to spare parts. I have a new resistor on the way, so I'll swap that in and see if it was just a bad resistor. The motor I installed initially was bad, so it may have weakened the one that's in now. Engine compartment fuses (10A and 40A) are both good.
My question at this point is "Am I missing something?" Is there some other part of this system that I've overlooked here? The rear A/C works GREAT--no issues, blows super cold, etc. Rear controls are predictable and effective. The front controller, fan, and resistor just never seem to want to work together, even when all of the parts are new and "working", there are weird behaviors--for instance, the inability to activate recirculation, but only sometimes. The system goes in and out of Auto mode, and there are other bits of oddness that seem to come from the A/C controller, but not consistently, and swapping in a new head didn't seem to solve those problems. Is there something else I should be looking at?
