Hi everyone
I have a Maxima SE 2000, AC worked before but about 10 months ago when I turned on the AC, the heat came out. I pop up the hood, I saw the clutch on compressor worked, the aluminum pipes are cold, sweat like normal. I disassemble the control unit on the dash board and check with DMM for soldering, pads, traces on the boards, transistors, etc.. and found nothing was bad, Fuses ok. however I could not check all the components. I don't know where else to check, I looked up on the climate control unit for MAX 2000 and found mine was different with slider temp control switch instead of the digital autocontrol. I found the thread on this forum but I can not do the self diagnose, I am buying an autocontrol unit on Ebay for $40 so that I can do the diagnose, should I? I don't know where to check. I am thinking my control unit is bad not closing the heater door? Please help.

Joseph

http://www.ebay.com/itm/200963751079...#ht_102wt_1328

 

I am removing the AC climate controller unit from the dash board. I individually press on the Mode to change from Front, foot, defrod etc.. I see the motor switching doors, but I slided the switch between hot and cold, I don't see anything moving.. I am looking for the heater / AC door.. to see if any moves, I turned on AC, or heater .. both came out heat only. therefore I guess the heater door funtion is not functioning, Does anyone know where the heater door is, and what it supposes to happen when the switch change from Heat to AC? please help!. I appreciate for any help, anyone, any reply.. please. I am trying to fix it now but just run in the house hoping someone post some idea, but nothing !!

 

First - DO NOT buy the other kind of control unit for the auto climate control. It won't work in your car, there are a lot more differences than just the control panel.

It sounds like you are having a problem with the air mix door or the motor that moves it. It is more likely the motor than the door itself.

The air mix door is inside the big air duct box against the firewall behind the radio. You cannot see the door itself. The motor is on the bottom of this air duct box.

If you get down and stick your head into the driver side footwell, look past the gas pedal to the center of the car next to the firewall. To see if the motor turns and tries to move the air mix door, you will have to crawl into the passenger side footwell.

Here are photos from a 4th gen. They are very similiar and will help you get an idea of what you are looking for.

From driver's side:


Air mix door motor (new one on left):

 

Hi Dennis, thank you for your post. I found that motor, it is under the air duct box, I turned the slider hot and cold switch, the motor doesn't move, I unplugged the power to the motor and move the motor arm by hand, it doesn't move. It is very hard to take it out. I will search how to remove that motor. If you have any link, I appreciated for your help.

update.. I electrically checked on pin 4 (Orange /Green) of the motor, Temp Hot measured 12V, cold 0V. Pin 5 (Red/ Green), Cold 12V, Hot 0 V, therefore the controller is good, but the motor is bad. The link I found said the measument should be 10V, I think 10V loaded, 12 V no loaded? I need to remove the ECU unit to access to the motor. What is ECU, Is that the computer? Can I unplug it, am I loosing memory or reset anything? Please help!
Joseph

 

Finally.. I would able to remove the Air blend actuator (mix air door motor).
1. Remove all tiewrap plugs with a long nose plier, that would make it easier for the tool to fit in where you are working on
2. go to the driver side, lay down and remove 2 screws that hold the ECU or ECM unit to the bracket with 5/16 wrench (weird Japanese car used standard system tool?)
3. Pop up the hood, remove negative battery terminal
4. Go to the passenger side, remove the cable to the ECU unit
5. Go to the driver side lift the ECU cable, use the 1/4 rachet and 10mm socket and short extension to remove both screws that hold the bracket to the bottom chasis; use 8mm wrench remove 2 screws hold the actuator .. push down the cable to make room.. Driver side now is clear..
6. go to passenger side, remove other 2 screws that hold the ECU to the bracket, remove the ECU, use the long nose plier to remove all the tie wrap, this time you would able to use a wrench to remove the 3rd screw of the motor.. I forgot to say to unplug the actuator first.
7. open the unit by using flat screw driver to slightly lift those 4 clips.. Apply 12 volt and negative directly to the motor (it made in China), it must turn, otherwise motor of the actuator is bad.. Replace the actuator. My motor is bad and I am going to get the new actuator unit from Ebay $30, dealer $86+ tax+ 2 days order. If you want to repair down to component level, you can just solder the new motor, may be 5 bucks. I tried to upload photos, but it keeps give me errors