ffcbairn

I've been sitting on this problem for a while. I have the standard manual climate control. No matter what position the slider is at it always blows hot. No matter what button is pushed it always comes out of the face level vents, never defrost or floor. With the blower off I still get air coming through the vents whether recycled air button is pushed or not.

My understanding is that there are a few motors that control the system. One for temperature, one for which vents it blows through, and one for recycled/outside air.

Being that the only buttons which work are the **** that controls fan speed, rear window defrost, and the A/C on/off, I figured that the control unit (as seen in picture) is shot. I ordered one and installed it, no change.

As I don't know much about the overall components of that system I broke down and took it in to Nissan to at least diagnose it. They came back rather quickly and said it was the "Heater Control Module"

Am I missing something here or is the picture I have not the Heater Control Module?

DennisMik

iTrader: (2)

The photo is the control module for the heater and a/c. It is made up of independent parts, the fan switch, the temperature slider, the outlet push buttons, a/c on, etc. The control unit is fed power by fuse # 19 (10 amp) and the control unit will then send power to the air mix door motor (temperature) and the mode door motor (which vents).

Having 2 bad motors at the same time is unlikely, so I think that your problem is electrical such as the fuse or maybe a broken wire. Find a pink wire with a blue stripe in the wire harness connector and check that it has 12 volts when the ignition switch is on. Also check that the wire is seated all the way in the connector. It is near the center of the biggest connector with the most wires in it, opposite side of the locking clip.

Also, the recirculate (recycle) is working exactly as it should.

ffcbairn

Thanks for the response Dennis. I checked fuse 19 and it appears to be good, just to make sure I swapped it anyway. I tested the pink wire with blue stripe and it does get power. There is a second pink w/ blue wire on the smaller harness next to it, I also tested that one which seems to be good. All wires look to be seated properly and none appears to be stripped or damaged insofar as I can tell by looking.

I agree with you that it seems unlikely both motors died at the same time which was how I came to the conclusion it was the control unit.

Appreciate any further guidance you can give me. Is there any way to test the motors themselves? I did notice that I can hear the motor move when I push the recycle button on and off so I believe you are correct in that working. I can't hear anything move (or attempt to move) if I push the vent selection buttons or move the temp slider.

Edit: Just reread my original post and part of it sounded unclear. Though I say the vent selection buttons don't work, they do light up to the corresponding button, they just don't actually change where the system vents. Not sure if that really changes any tips or not but wanted to try to paint an accurate picture.

DennisMik

iTrader: (2)

I don't know what to tell you to look at or try next. My 97 max had a bad air mix door motor that died in the heat setting. I did the diagnostic procedure in the FSM. It looked easy enough but I had a hell of a time doing it. I suppose that's what you should try next, though. Ditto for the mode door motor (controls which air vents).

The air mix door motor diagnostics starts on page HA 179 and the mode door motor diagnostics is right after that.

I don't think that the FSM has an actual motor test in it. The FSM procedure basically has you check for voltage and if you have voltage and the motor doesn't move then the motor must be bad. If you don't have any voltage then the control panel must be bad. You could jumper power to the motor yourself and see what happens but I think the FSM procedure is good in that respect.

ffcbairn

Alright Dennis thanks for trying. This has been one of the more difficult problems I've had to deal with. I feel like I am chasing some obscure electrical problem. I was sure the new control unit was going to fix it as other than the fuse there aren't too many common points of failure. I will be really surprised if both motors end up being bad considering the whole thing stopped at the same point. That makes me wonder beyond the motors and I just can't figure out where else it could collectively fail unless they both run off the same power line.

aongch

Sorry to bring this back up, I'm having the same issue (always HOT air) but is fuse #19 the correct one? Per the diagram this fuse is marked Meter.

DennisMik

iTrader: (2)

fuse # 19 is in the middle row, 2nd from the right end. It is labeled "AIR CON".
The fuse labeled "METER" is in the bottom row, 2nd from the right end. That is fuse # 30.

aongch

All the fuses are fine, none burned out. Can the temp control unit be bad then? Where is the location of the below parts, and which one? Note that all other controls on my manual unit works - fan, A/C, directional buttons, recirc, etc - just that hot air is the only thing coming out. Thx for your help on this, I'm toasting.

Which is the correct part? My build date is 04/00

2000-2003 NISSAN MAXIMA TEMPERATURE CONTROL MODULE 28540 5Y700 or
Nissan Part Number: 27742-2Y900 ACTUATOR ASSY-AIR MIX

http://www.ebay.com/itm/2000-2003-NISSAN-MAXIMA-TEMPERATURE-CONTROL-MODULE-28540-5Y700-OEM-/151343991208?hash=item233cce09a8&vxp=mtr
http://www.nissanpartsdeal.com/parts...742-2y900.html

DennisMik

iTrader: (2)

I don't know if the TEMPERATURE CONTROL MODULE 28540 5Y700 is really what it says it is. The part number, 2854-5Y700 comes up as "Controller Assy-Shift Lock".

The 27742-2Y900 ACTUATOR ASSY-AIR MIX is the motor that moves the air mix door to make the air temperature what you want it to be.

aongch

So it looks like the 27742 might be faulty, where is this unit?

DennisMik

iTrader: (2)

It is attached to the bottom of the main air duct box, just about dead center next to the firewall, above the ECU.

Here is a view from the driver side footwell:

2001M20

I had some similar issues with mine but it wasn't exactly the same.
I ended up replacing a few things and all the problems were located under the glove box by the blower. I replaced the control module there and the relay as well as the whole blower motor which I got from the junkyard for $20. The module and the relay were both bad. Also there were problems at the part store pinpointing the part they gave me the wrong one twice so there is an issue identifying aftermarkets on that stuff. Hope you get it resolved I'm putting in a link to my post about it although it's not very technical and my car was an 01.

https://maxima.org/forums/5th-genera...ics-match.html

DennisMik

iTrader: (2)

All the things you talk about are for the blower motor. The op has temperature regulation problems, not fan problems.

aongch

Correct. My blower motor and fan settings work perfectly. Only issue is ALWAYS Hot air coming through. I'll probably get that air mix motor first and see if that's the cause. Thx Dennis

aongch

Any idea on how to replace this part? Does the whole air box need to be removed? The only video I found related to any console area fix is this, but no where near that air mix part.

DennisMik

iTrader: (2)

Never replaced that motor in my 2000, so I don't know. It looks to me as if you unbolt and move the ECU, you can get the air mix door motor out.

aongch

I did remove the ECU/ECM before this issue, to do the IACV replacement and hose bypass. I wonder if I messed something up in the ECM mount area under the dash, will check. But, in the mean time is there a way to manually bypass the air temp motor and swing the flapper either way just to test it?

This one is a pain in the butt, can't figure it out. My indy shop wanted $300 for the entire control panel and switches plus $150 labor, they won't diagnose the actual faulty part. Not even sure if this is the actual faulty part (control panel).

Seems like has to do with that temp slider unit. When the AC is on I can slightly feel cold air coming in somewhere behind the ashtray area, very little air. Everywhere else....hot air!!

DennisMik

iTrader: (2)

In order to move the air mix door inside the ducts manually, you would have to remove the motor and move the operating arm by hand.

Get down in the passenger side foot well and look at the motor. You will see the arm that moves the door inside the duct. You may have to take the plastic cover off that hides the ECU to get a good view. Turn the ignition key to the ON position (you don't have to start the car) and move the temperature lever from one end to the other. You should see the motor/arm move if everything is working.

If the arm doesn't move, this still doesn't tell you if the motor or the control panel is bad. In the service manual, there is a test you can do to see if it is the motor or the control panel. The section starts on page 179, the tests are on pages 180 & 181.

http://boredmder.com/FSMs/Nissan/Maxima/2000.5/HA.pdf

aongch

Apprec that, Dennis, and the xlnt PDF got me looking around at the other electricals, Thanks!

But back to my issue, even with the ignition ON, I can't budge the air mix door back there deep by the ECM, motor must be stuck, probably the cause of the problem. My next steps is to disconnect the linkage and move the door manually, see if that works. And use my multi-meter to check those connections.

The air mode switches and motor works fine, I can see the linkage moving when pushing the diff buttons.

ffcbairn

Since this post was revived, and I have resolved the issue just recently, I should post up that both actuators and the control unit were busted. Wiring was fine. No idea how that could have happened except that maybe I somehow shorted something installing my stereo, but I think more likely that one device shorted and blew the rest since they all stopped at the same time. Installed the new actuators one at a time with the new control unit. All was right until the other day, which is what brings me back to this post.

Dennis is there a third actuator that controls the air regurgitate? I just moved out to Washington state, and there have been a lot of fires here lately. Recycle was working fine until three days ago when it quit and now I can only get outside air, so limited filtering of all the smoke. Also, is that actuator on an unusual circuit? I checked the normal fuse which is fine. Thanks man!

DennisMik

iTrader: (2)

Yes, there is a third motor for the recirculate. It is on the passenger side above the glove box, approx the center of the glove box.

It gets power through the control panel just like the other motors do, so since the other motors work, you don't have a fuse problem. If you read any Nissan documentation, it is called the Intake Door Motor.

Legionnaire1856

Shot in the dark but did you ever get your recirculation fixed? Mine isn't working and I've been trying for 4 years to get it to work. I've tried 3 different climate control modules and they're all doing the same thing. No power to the intake air door motor until I blip the throttle from idle when the car is running, then the door closes for a split second and then opens again.