Climate control wiring diagram?

[banhama]

Does anyone have a wiring diagram for the climate control unit, in particular the outputs to the heater mixer flap motor, and the air distribution flap motor.

Looks like the controller has failed, and being a track only car I don't need the climate control, and the aircon has been deleted anyway.
But I do have fixed polycarbonate windows so need some ventilation on hot days, and demisting on wet days.

I can easily fit a toggle switch to bypass the resistor and run the fan at full speed.
I would then like to:
Run the heater flap motor from open to closed, no mixing required, via another switch.
Run the distribution flap from 0% (vents) to 100% (demist) again no intermediate settings needed, via a third switch.
(As a bonus it would be good to operated the recirc air motor via another switch, but not crucial)
That way I can switch the blower on and select heated air to the screen or unheated air to my face, that's all.

Just need to know which wires to switch on the flap control motors.

Many thanks, Andy

 

[frayz]

Did you ever get a diagram for this mate? I have a fault I need to trace.

 

[banhama]

Unfortunately I didn't get a diagram.
I got things working to a point, but control the heat manually, full hot or full cold. That's good enough for my application.
Can't help with your fault finding I'm afraid.

I have just bought an RSTuner for re-mapping and that's showing me loads of stored and live climate control faults.
This would be an expensive solution to your problem, >£200 for the RSTuner plus the cost of the HVAC module. Very useful tool though.

 

[frayz]

I’ve just had my dash out for a suspected heater matrix issue. All was working perfectly before. Since refitting I dont appear to have function of the hot/cold stepper motor. The motor works fine as I’ve tested it, I either have no power or no signal to it and I need to trace it.

 

[JamesBryan]

I’ve just had my dash out for a suspected heater matrix issue. All was working perfectly before. Since refitting I dont appear to have function of the hot/cold stepper motor. The motor works fine as I’ve tested it, I either have no power or no signal to it and I need to trace it.

Is the plastic cog engaging the motor?

They usually crack, causing the loss of temp control.

Accessed from the drivers footwell.

 

[frayz]

Is the plastic cog engaging the motor?

They usually crack, causing the loss of temp control.

Accessed from the drivers footwell.

Yeah that’s all fixed. It’s the stepper motor not receiving signal or power. If I plug the stepper motor into the HVAC air flow plug, it works. But plugged into the temp control plug, it doesn’t.

 

[barnesautos]

Just as a precaution , check to see if all the pins on all the connectors you removed are ok iE not bent over. That’ll cause a similar issue.

 

[JamesBryan]

Yeah that’s all fixed. It’s the stepper motor not receiving signal or power. If I plug the stepper motor into the HVAC air flow plug, it works. But plugged into the temp control plug, it doesn’t.

Ahh nightmare mate 😏

 

[frayz]

Just as a precaution , check to see if all the pins on all the connectors you removed are ok iE not bent over. That’ll cause a similar issue.

I don’t believe this to be the case but it’s a good place to start, I’ll check in the morning.

 

[barnesautos]

I don’t believe this to be the case but it’s a good place to start, I’ll check in the morning.

The control for the bus starts at the ecu , I read you confirmed the stepper motor is ok , so that leaves the bus wiring or the ecu .
Also just thinking , there isn’t an earth anywhere you took off up top to move a loom over or something?

 

[barnesautos]

@frayz

 

[frayz]

Obviously I could have made a mistake but I’m 99.9% certain all earths were replaced when the crash bar went back in. I can confirm both the star drive and stepper motor function fine. It’s either a signal or power not being received. Thank you so much for the schematic. 👌🏼

 

[GrahamS]

these docs will help

 

[frayz]

Okay so I’ve checked the wiring to both the stepper motor plugs and to the HVAC control unit for damage. I can’t find anything.
I know the suspect stepper motor is functioning correctly as when I connect it to the air diversion plug it operates in both directions.
However when I connect it to its correct plug (HVAC temp) it does nothing.

When I connect or reconnect either of the 2 HVAC multi plugs. The suspect stepper motor rotates clockwise approx 30 degrees and stops. It will then not responded to the HVAC commands.
If I then disconnect and re connect either of the HVAC plugs, it’s repeats its clockwise 30 degree movement and stops. Never once does it go anti-clockwise. It’s acting as there is no feedback to tell the HVAC unit of its position. Yet if I connect the stepper motor to the air diversion plug, it operates in both directions perfectly.

I have a spare HVAC unit so tried that too and still get the same symptoms.

 

[banhama]

This is probably no help at all, but I would be interested in the answer:

When the compartment temperature sensor is disconnected does it make the controller 'think' that it's fully hot or fully cold?

Might sound a daft question, but after stripping the car, including removing the internal temperature sensor/mini fan mounted up above the screen, I had a very similar scenario.
The control panel would not control the temperature, I took off the stepper motor, checked the splines etc. all ok. but Just as @frayz found when I connected it it only moved in one direction, then didn't respond to the controller.
I'm guessing now that the controller 'thought' the cabin was either stinking hot or freezing cold, and just wanted to drive the flap fully in the corresponding direction.

My solution, being a track only car, is a bit stone-age! I found a star-bit, T50 I think, fits neatly into the flap socket and I just reach under the dash to flip it from full hot to full cold. The air distribution flap still responds to the controller so I can have full cold in the face, or full hot to the screen. It's all I need but it's not exactly Climate Control!

Anyway, @frayz I'm sure you've already done it, but if not it might be worth checking the compartment temp sensor connections, it might have been disturbed having the dash out.

Good luck

 

[frayz]

This is probably no help at all, but I would be interested in the answer:

When the compartment temperature sensor is disconnected does it make the controller 'think' that it's fully hot or fully cold?

Might sound a daft question, but after stripping the car, including removing the internal temperature sensor/mini fan mounted up above the screen, I had a very similar scenario.
The control panel would not control the temperature, I took off the stepper motor, checked the splines etc. all ok. but Just as @frayz found when I connected it it only moved in one direction, then didn't respond to the controller.
I'm guessing now that the controller 'thought' the cabin was either stinking hot or freezing cold, and just wanted to drive the flap fully in the corresponding direction.

My solution, being a track only car, is a bit stone-age! I found a star-bit, T50 I think, fits neatly into the flap socket and I just reach under the dash to flip it from full hot to full cold. The air distribution flap still responds to the controller so I can have full cold in the face, or full hot to the screen. It's all I need but it's not exactly Climate Control!

Anyway, @frayz I'm sure you've already done it, but if not it might be worth checking the compartment temp sensor connections, it might have been disturbed having the dash out.

Good luck

Interesting you say that as that scenario had crossed my mind and indeed I checked the temp sensor. I went through it as far as I could without stripping the dash back to start checking individual wiring etc.

Then the most annoying thing of all happened.
It randomly started working again and I’ve absolutely no idea why. I did then disassemble the stepper motor to zero the gearing as it had lost its home position.
Thinking about it though, I believe this error signal is the main culprit behind the broken star drives on the heater box. I’m now thinking they’re a result of another issue. The motor loses its park position and gets lost. Then exceeds its usual range of motion and breaks the drive in the heater box.
For now it’s working perfectly, but frustrating it’s through luck rather than me finding and fixing the fault. 😕

 

[banhama]

Ah, I know how you feel, it's great that something's working, but really not satisfying or confidence inspiring when you haven't definitely found a fault and fixed it.

I have a running battle with the bloody UCH, I've had it checked over by BBAReman and expected it to be faulty, but apparently it's working correctly.
Yet every now and then I get a solid red light on the dash and can't start the car. (Usually just before a race, or something critical...sod's law)
Give the UCH a kick and everything works fine for ages.
Loose connection somewhere I guess, but very frustrating!

 

[nw83]

I think I have this issue. Track car and I'm pretty sure the temp sensor isn't plugged in. Not sure if that has an effect. But the motor for the heat control flap just doesnt seem to move (other than a brief bit of movement if you cycle the ignition off and on)