Thread: Blender door or HVAC control unit problem?

I have a 2001 GTP with dual slider air/heat controls. I took a road trip today, and noticed that with the A/C on, sometimes the drivers side would blow cold, then go warm, then go cold again. The passenger side is always cold. It seems intermittent, and I can sometimes fix it by wiggling the drivers side slider. To me, this sounds like a blend door issue.

Then, on the way home (about 3 hours), I didn't put the A/C on because it had cooled down. I left the sliders on cold and kept the vent on. I had no strange swings in temperature like I did with A/C on. It would stay cold the whole time, and I could adjust the sliders and it would behave as I'd expect. Now, it doesn't seem like a blend door issue.

Could this be an HVAC control unit problem? Any other ideas?

Just to throw something out, but maybe it's low on freon? My sienna would do this too, and it turned out it just needed charged. One side stayed cool, and other side would fluctuate. Seemed better at certain rpm's, if I remember right. But, yeah, put a can of freon in and it has been good since.

Originally Posted by bandook

Just to throw something out, but maybe it's low on freon? My sienna would do this too, and it turned out it just needed charged. One side stayed cool, and other side would fluctuate. Seemed better at certain rpm's, if I remember right. But, yeah, put a can of freon in and it has been good since.

Will try it. The system does leak and I've had to recharge it before, but I don't remember it being intermittent before.

Yeah, it was a common problem on the Sienna's with split climate control. Theory I heard was that coolant was low enough that the compressor would stay on, but only one half of the evap would get cool, which was pass side, and would be warm by the time it passed by driver side when the blower hit it.

Added a can, looks like that may have fixed it. I'll keep an eye on it. Thanks guys!

Bump. After a bit more seat time, I found that even on vent, the drivers side goes warm. If I fiddle with the controls it'll go back cold again. Definitely a blend door actuator? Is there a write up on how to replace or diagnose?

http://www.grandprixforums.net/threa...or-Replacement

I just replaced my passenger side blend door for this issue but when testing found the motor would oscilate back and forth and then stay warm. I removed the motor and could manually move the door to cold or hot so I was relieved that was OK. Could this just be the control head?

its the actuator, its crapping out. they freak out too when bad and twitch back and fourth.

Originally Posted by ScottyDoggs

its the actuator, its crapping out. they freak out too when bad and twitch back and fourth.

Problem is the new one is doing it also, I just found in another thread sometimes pulling the fuse or the battery will reset the motor. I'll try that or every six months I'll just manually flip it from warm to cold! I usually drive alone anyway and the drivers side work great!

Just kidding I need to figure it out.

i did the manual turning of both sides for two years, its not that bad till you want warm air not hot.

maybe see what the little plug is doing power wise? if its off and on or back and fourth out the plug it should be the cc gone a rye.