Climatronic help ?

[BigCol]

Wonder if you can help ?

I've got a fault code on my climatronic "00538 Reference Voltage 07-00 Signal to low"

I've had this for some time now but have ignored. Now I need to sort it, the clima will blow hot and cold and will randomly put air out through any vent except the one you select !

My limited understading of electrics is that if something needs to be measured, it is contrasted against a reference voltage (I think this is how the sensor inputs and flap angles are calculated by benchmarking against a lower voltage ?).

Now there is a wire connection A58 which goes through all the flap motors and some of the sensors. A58 I think is a 5 volt supply from the instrument cluster that is the refernce voltage ? Dunno, is it ?

I had a recirc air flap motor that was faulty for ages and reckon this might have burnt out that 5 volt supply ?

What I'd like to know is :-

1, Where exactly A58 is ?

2, Is the supply 5 volts and generated by the cluster ?

3, Could it have been burnt out ?

4, How would (if it is 5v) would it be created ? resistor ?

Bit premature really as I've yet to go to town with my multimeter now that I've got the wiring diagram below in a langauge I understand. I do hope to solve this one way or another. (p.s. I've swapped the clima head unit for another so it's not that.) If anyone could verify the principles of the "reference voltage" I'd be most grateful.

I'm going to post this over a few forums in an effort to get some answers. Also feel free to use the wiring diagram as you see fit, it may be useless but it's certainly easier (to me anyway) to understand than VW's.

Oh, and the answer to that age old question of "Can I covert manual air-con to climatronic?" is, YES, if you can physically mount a new heater unit with all the motors and then deal with the scary amount of wiring as shown below.

Thanks in advance.