AC electrical problems

Post Sat Feb 26, 2005 7:08 am

I was fitting a new stereo head unit in my sport and decided to try and tackle the A/C problem. what is happening is that the compressor kicks in whenever the fan is on irregardless if the A/C button is on or not. So i cannot have the fan on without a/c . thought it may be the switch so when i changed it same deal but then i noticed the special wiring courteous of the previous owner. they have cut the black wire from the rear of the a/c switch connector block and attached it to one of the yellow wires. If i open this connection the fan will come on without compressor but the compressor will now not come on with the switch (i tried both switches)

The wire colouring i might add seems to bear very little resemblance to what i expected to see according to the Haines manual.

so anyone have any ideas?? Mr Moooooore? Cros?? any one??!!

mr lee

can send picture if required

Post Sat Feb 26, 2005 2:01 pm

No experience of E30 aircon whatsoever, but first thoughts are that, when the previous owner had the car, the aircon compressor stopped working because of one of the various sensors in the aircon circuit - either a faulty sensor, or one telling the truth - and someone bodged it into working by the wiring you have found.
Will try to look up some aircon circuits if I have time later on.

Post Sun Feb 27, 2005 10:32 am

Cheers also studying the manual, do you know any sites to get a better wiring diagram? it is as you say bodged but it works fine, i was just going to put a switch on the bodged wire to enable me to turn off the compressor but obviously this is a quick fix and i would like to know how to really fix it. It is a Japanese manufactured BM BTW if that makes any difference.

cheers

mr lee

Post Sun Feb 27, 2005 11:01 am

Much better wiring diagrams (U.S. models, I think), at:
http://www.autolib.diakom.ru:8001/CAR/B ... 0DIAGRAMS/
These show the internal connections of some of the bits, so you should be able to follow the power around the aircon circuit and see where it dissapears.
The blower switch shows black and yellow wires connected to it, so hopefully this diagram bears some resemblance to your car, and you will be able to reconnect the wires where they should be, and then trace the fault. Good luck.
P.S. Just noticed your location. Was wondering why you were concerned with aircon, while I'm here freezing my bo****ks off.

Post Sun Feb 27, 2005 11:02 am

Hi Mr Lee,

I think the black wire is actually going to be black/violet. This wire is the one that tells the A/C that you want it to start (does not directly control the compressor). The yellow wire is the one that switches the internal blower fan onto low speed when you switch the A/C on.

As you have found, shorting the black/violet wire to the yellow wire is going to cause the compressor to run when the blower is switched on (I would also expect the aux fan in front of the radiator to be running as well).

You said that removing the black/violet wire from the yellow wire stopped the compressor from engaging. You didn't indicate that you had re-connected the black/violet wire to the back of the switch connector.

If you did re-connect the black/violet wire, did you then also try the new A/C switch ?

If you let me know your e-mail address, I'll send you a copy of the BMW wiring diagrams for the A/C system. Should be the same for Japan.

Cheers,

Ian.

Post Sun Feb 27, 2005 11:16 am

Cheers guys.
Yes it is quite warm here in Bahrain and yes the a/c gets used all the time!!

Ian, yes i tried as you suggested already - reconnecting the black(and violet - it was late in the afternoon) and nothing with the original switch or a replacement. there appears to be two yellow wires from the connector block, i will check properly and let you know. i have the Haines but it is more of a simple block diagram as you probably know.

my email is mrlee2@hotmail.com

cheers

mrlee

Post Sun Feb 27, 2005 11:33 am

Mr Lee,

You should have e-mail

The Haynes wiring diagrams are almost useless when trying to fix this sort of thing. The BMW ones are excellent. For the A/C, it also has a load of fault finding info included, and explains how each part of the circuit operates.

The second yellow wire is the one that switches on the blower fan when you use the recirculate button on the A/C switch.

Cheers,

Ian.

Post Sun Feb 27, 2005 12:37 pm

Ian, is there any chance you could send them to me please?
They should be the same for the M3 yes? Also would it include the wiring for the fan? I've found out that the wiring for my fan has been cut near the headlamp, so haven't got a working fan.

simonoatley@tiscali.co.uk

Cheers!

Post Mon Feb 28, 2005 9:18 am

Simon wrote:Ian, is there any chance you could send them to me please?
They should be the same for the M3 yes? Also would it include the wiring for the fan? I've found out that the wiring for my fan has been cut near the headlamp, so haven't got a working fan.

simonoatley@tiscali.co.uk

Cheers!

Simon,

You should have a copy of the wiring diagrams now (sent yesterday, but could not respond here as the zone went down before I had a chance to reply).

Yes, this does cover the electric fan, and it is the same as the M3.

Cheers,

Ian.

Post Mon Feb 28, 2005 3:17 pm

ian332isport wrote: Simon,

You should have a copy of the wiring diagrams now (sent yesterday, but could not respond here as the zone went down before I had a chance to reply).

Yes, this does cover the electric fan, and it is the same as the M3.

Cheers,

Ian.

Received, much appreciated Ian!

Cheers Simon