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As the title suggests, the climate control in my '96 Maxima (255k miles) is stuck on heat. I believe this is a blend door or something that might be stuck?
This is the auto climate control where one just selects a temperature and the system does the rest. It used to work fine until this winter, when I noticed that the heat is cranked to max no matter what temp I set it to. If I turn the unit to 60 with the A/C on, air is still blowing warm. If I turn the unit off completely, hot air still blows in slowly at speed (believe this is by design) and I can only stop the hot air by hitting the RECIRC button so no air at all enters the car. Very annoying!
Is this a common issue, anyone know what I might be up against in fixing this?
Quaker - There are several posts on this topic. Somebody recently provided a detailed post on this topic. It's becoming a common problem at these cars age. I have a 91 Q45 with the problem right now. One of the Q experts told me he has seen 3 cases where the foam gasket around the mix door sticks to the contact surface. I believe him. The problem with that car, it is a major dash project to get into that part of the HVAC system where the mix door resides. I'm not sure what I will do about that one.
I'm experiencing kinda the same issue. Except my fans are stuck off and the heat as well on mine is stuck on. I'll be driving and feel warm air on my feet even with cold selected. Auto diagnosis only returned codes for ambient temperature sensor.
Tried the auto amp with no luck. Ill have the dash apart this weekend or during the week for another project and I was gonna test the blower motor I guess I'll take a look at the blend door
As the title suggests, the climate control in my '96 Maxima (255k miles) is stuck on heat. I believe this is a blend door or something that might be stuck?
This is the auto climate control where one just selects a temperature and the system does the rest. It used to work fine until this winter, when I noticed that the heat is cranked to max no matter what temp I set it to. If I turn the unit to 60 with the A/C on, air is still blowing warm. If I turn the unit off completely, hot air still blows in slowly at speed (believe this is by design) and I can only stop the hot air by hitting the RECIRC button so no air at all enters the car. Very annoying!
Is this a common issue, anyone know what I might be up against in fixing this?
We had to get the ECU out of the way between the driver and passenger side footwells and then we were able to access the servo motor that moves the blend door. There are a series of diagnostic tests you can run on the auto-climate control system specified in the FSM; you have to hold down a sequence of buttons as the car starts. Let me see if I can dig up any other info for you.
HA-70 in the FSM describes switching the auto climate control into diagnostic mode:
Start the engine and immediately press the "OFF" switch for at least 5 seconds. The off switch must be held down within 5 seconds of the ignition switch being turned to "on". The diagnostic can be cancelled by pressing "Auto" or turning the car off. Move from one test to another by pressing the "Hot" or "Cold" arrows.
Mine didn't throw an error for whatever reason, but replacing that motor fixed the issue. You may want to troubleshoot just a little before throwing parts at it, but that's what fixed mine! It's been 4 years so I can't walk you through our exact process; once the ECU was out I don't remember it being too difficult. I think getting the screws out of the ECU was a pain.
01-16-2019, 07:04 PM
