A/C Heat Blend Door

dizzle6988 · November 6, 2017

Hello yet again, so I have an issue. The blend door motor in the cab of my truck has what I like to call gotten stuck. My driver's side vents blow hot air and the passenger blows cold. Could I just pull that out and wiggle it, clean it, that sort of thing and plug it back in with the hope that it works fine again? If not I don't have the cash for the part because I know it's $120. So has anyone else faced this same issue by chance?? 2004 GMC Sierra 2500HD 4x4 Quad cab 6.0l Gas motor. Thanks again in advance!!

RonJ · November 7, 2017

My 2004 Diesel does the same thing. I turn the truck off. Open the door to kill the accessory electric feed . Then I turn it back on. I'm guessing that it reboots the computer that opens the door in the duct. It sometimes screws up 5+ times a day.

dizzle6988 · November 7, 2017

It's been like this for a couple weeks now. Usually turning the truck off and back on again will solve it. But not this time.

davester · November 7, 2017

the blend door actuator is probably broken/damaged, so it works when you first turn the truck on, because it does a 'learn' cycle at the time, but then it can't properly adjust the blend door all the time, so it gets more and more out of whack.

I would suggest replacing it. Or at least uninstalling it, but leave it plugged in, then see how well the actuator works while you adjust the controls.

dizzle6988 · November 8, 2017

I'll have to work on this when I take my passenger side doors apart to see if I can fix my windows. I was thinking that if I unplugged it and plugged it back in that it might get back to working again. Kind of like how the lights for my climate controls very randomly work. But if I unplug the controls to make more room while working on my stereo for example they will come back on for a few days. I had wanted to convert to the digital climate controls. But I found out that the connector is different. Oh well.

davester · November 8, 2017

Yeah, IIRC, the digital climate controls is more than just a different display/control unit. The wiring harness and HVAC system is different as well. Non-trivial to switch from one to the other.

swathdiver · November 8, 2017

Sometimes you can take them apart and clean them and they'll function fine afterwards. It depends on why it is failing. A Tech2 will tell you which one is giving trouble and why.

dizzle6988 · November 8, 2017

Didn't know the actual system was different. For years most manufacturer's have used the same wire harness and just deleted certain options depending on the trim package . I thought this was the case with my truck until I found myself to be wrong. Yeah I'll screw with the blend door actuator or motor. See if I can get it to come back around.

4bycamper · November 10, 2017

Fleabay has a blend door motor starting at $28.00.

Easy to replace yourself. Enjoy

swathdiver · November 10, 2017

There are four actuators for the system.

The Driver's Side Air Temperature Valve Actuator is under the dash on the passenger side.

The same actuator for the passenger side is to the right of the center vents.

The Mode Valve Actuator is just to the left of the center vents (commonly called blend door).

The Air Inlet Valve Actuator is behind the glove box.

They do not all share the same part numbers.

dizzle6988 · November 11, 2017

It's that first one you said. The drivers side temperature valve actuator. However I was told it was the blend door actuator at one point by a mechanic who I told about the problem.

swathdiver · November 11, 2017

There are three different part numbers among the four. The Temperature Valve Actuator is the same PN# for both sides. Now this is specifically for my 2009 Yukon XL so double check your part numbers.

The Tech2 will tell you right quick which one it is and how it is failing. I read people saying that they replace the blend door (Mode Actuator) and that solves a left-hot right-cold or visa versa problem but that doesn't make sense to me. I haven't changed any yet however my driver's side got just enough out of sync in counts to throw a code. I reset it but after a week or so it stays open a little more than it should so instead of setting the temp to 68, I drop it to 66 or 64 to keep the same comfort level. Eventually I'll get around to replacing it.

Air Inlet Valve Actuator	89018365	15-72971	Dorman - 604-106
Mode Valve Actuator	89018374	15-73952	Dorman - 604-112
Temperature Valve Actuator - Driver's Side	89018375	15-72972	Dorman - 604-111
Temperature Valve Actuator - Passenger Side	89018375	15-72972	Dorman - 604-111