Greetings. I have an 04 Yukon with the auto AC system that has me stumped. It has for the last few weeks warmed up nicely in the driveway before I get in to take my daughter to school and myself to work. However once in gear and driving down the road it will only blow "warm" air out of the vents. I took it to the shop and they advised it was the actuator down by the gas pedal. So I had it replaced on Saturday, no help. I took it back yesterday and they advised it was now showing the code for the one located near the passenger side kick panel. So I had them replace that one. Shop called and said it is blowing hot air with the temp set on 73. Great. Well when I went to pick it up it was doing good until about 5 min into the drive home and warm air again. It does not matter if the temp is set to 73 or 90, vent, foot, defrost, vent and foot all I get is "warm" air when it should be roasting me out of the truck. The AC side works great but its a tad chilly in South Alabama right now and my 1 yo doesn't like a cold ride to school. I have searched the forum and it seemed like the actuators were the issue but is there something else? I am tired of chasing this and the few weeks of winter we get is really starting to suck. Thanks!!
04 Yukon no heat while in motion
- Thread starter Blind_dog
- Start date
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livingez_123
Full Access Member
possibly a bad water pump impeller?
Rivieraracing
Full Access Member
What are you trucks coolant temps doing while driving? Sitting idling? Are they in the normal range (a click to the left of dead straight up) or do they fluctuate from one another?
When full warm, do your upper and lower hoses feel hot to the touch and pretty equal to each other?
When was the last time you flushed out your coolant system? When was the last time your thermostat was changed out?
Also, do you have rear air in the truck and if so does it get hot when you call for full heat?
When full warm, do your upper and lower hoses feel hot to the touch and pretty equal to each other?
When was the last time you flushed out your coolant system? When was the last time your thermostat was changed out?
Also, do you have rear air in the truck and if so does it get hot when you call for full heat?
I just spoke with the dealer, they advised they feel the coolant does not need to be flushed at this time in order to correct the issue. They feel it is the control unit itself that is faulty. They advised that they swapped the old actuators back in and out with the new ones and would get the doors to open then not open thus the feeling of a wiring issue or the A/C / Heater control unit is faluty. I also planted the seed that they should refund me the cost of the actuators since they have swapped them back and forth with the same result. As a side note that may justify the control unit, most of the lights have stopped working over the past few weeks. I thought it was because they were 10yrs old but could that also indicate a bad control unit?
Rivieraracing
Full Access Member
What lights are you referring to that stopped working?
bermudablueZ71
TYF Newbie
sounds like he is refering to the backlighting in the hvac control head.
To me it sounds a lot more like a base cooling system issue. It doesnt really make sense for the doors to change position when driving vs sitting idling to create the difference.Can try switching off auto mode and see if the temps change. I would look at bad thermostat or possibly backflushing the heater core.
Rivieraracing
Full Access Member
Yeah I figured he was referring to the backlighting in the HVAC but thought I'd ask instead of assume! If so, they may have just burnt out within a short bit of time from each other which is what happened to a few of mine a year or so ago! Easy to fix by replacing the bulbs!
He says they have the problem figured out (doubt it though since they were changing out parts that didn't help the problem at all) but hoping the dealership isn't gonna try taking him for a ride! If they do change that part out and it doesn't solve the problem, would be interested in the answers to the questions I asked earlier! I don't trust stealerships when it comes to service work for the life of me, been burned (attempted to burn most of the time) too many times!
Update - heat works, not like i was expecting(output wise) but it works. The control head was replaced and it seems to work. I was refunded all the money I paid for the actuators and labor and got the control head at cost. They left the two actuators they replaced in the truck and will honor the 12 month warranty on them. I would like to find a similar year truck and compare heat output when not in Auto mode to see if it is similar. It is a difficult thing to explain but 75 in my Tacoma or my Pilot is a lot hotter than 75 in the Yukon. At least the baby isnt freezing on the way to school any longer.
Thanks
Thanks
Rivieraracing
Full Access Member
Right on man, glad you at least have some heat!
