A/C Problems in 2011 GMC Yukon XL

[dwallace18]

I have a 2011 GMC Yukon XL. Been in the shop 4 times for A/C problems. They have fixed most of the issues but a new one has now shown up after the last shop visit. Originally the A/C would not cool and would cycle cool and hot air from vents. After replacing compressor and several sensors they finally replaced HVAC controls which seems to have fixed that issue. Know it does not cool in very high temperatures in stop and go driving. Works fine once out on the highway moving at speed. But will struggle when in stop and go. Weather cooled off and issue disappeared but returned once it got hot again. Does not do it all the time just has to be hot and seems to need to used and stopped in hot weather. Then when you add stop and go travel the A/C will not cool. Get it on highway at speed and A/C will then start cooling. When it works it works great. Shop could not duplicate issue and did not know what to do. Shop has been real nice but still not fixed. Any suggestions? I am assuming cooling fans on radiator issue or something like that.

 

[dwallace18]

Another question also. My low speed fan comes on with a/c being switched on. I assume it is my low speed fan because it is slow. how do you get high speed on? is there any way to test it?

 

[sumo]

have you tried the HVAC reset?

 

[Parthery]

So you get low speed fan air at speed...no high speed fan and no air when the truck isn't moving or stop and go?

This sounds like a blower motor and resistor to me.

Easy fix as both parts are in the passenger side footwell. 4 screws to drop the plastic panel. Blower motor snaps out. You need to remove two screws to get the resistor out. Hopefully the harness isn't damaged (sometimes when the resistors fail it burns the wires.)

I just did both on my '08...total parts were around $140 or so and it took me longer to setup and clean up then to actually do the job.

Look on YouTube....many videos there showing how to do it.

 

[dwallace18]

Not sure how to do a HVAC reset. If you can explain how to do that. I obviously have not done that.

 

[dwallace18]

This is all concerning the electric radiator fans and not the fans in the dash that control the air blowing from the vents. I may not have explained that well. I believe or are guessing that my high speed fan on my electric radiator fans are not working but low speed does. Vents inside blow hard and work fine but air is not cold.

 

[Denali Deen]

I know this is an old thread but I am having the exact same issues. Did you ever find the exact issue?

 

[gpracer1]

Find someone with a Tech 2 (or a dealer) and have them command the fans on high to see if they work. May be relays.....possible high pressure switch not tripping and commanding fans on.
All assuming correct charge and compressor is good.