HELP!! HVAC air con controls not working- UK Car!!

[foggy]

Help!

I've got UK 1996 E38. Unfortunately UK cars are way below spec than US cars - my air-con controls are analogue and manual (four dials - left heat, air flow control, fan speed, right heat) plus three buttons to the left of the dials (air con on, air circulation, rear window demister). The air-con control that you guys got in the states with the pixel display (with the notorious pixel failures) wasn't fitted to our cars till about 1997.

Suddenly last night all the air con functions stopped working - I can't change the air direction or temperature, and the air con, recirc air and rear window demister buttons aren't working either. I can however turn the blower on and off and adjust it's speed. In addition I've noticed a ticking from the engine compartment, at the rear by the bulkhead, it's some kind of heater valve fed with coolant form the engine. It was red hot this morning and still ticking (must have been going all night) so i've disconnected it. This tick happens every three seconds or so, even when the engine is switched off / no key in the ignition. My guess is that a stepper motor has got stuck and has blown a fuse or something. Anyone have any ideas? Whilst I'm on it, I've never been able to get warm air out of the vent in the rear of the front armrest (for rear passengers) - only cool air. Can anyone help??

PS I've attached my "paint" image of the controls to avoid any confusion - sorry it's poor but it gives you the general idea!!

[RLM]

Did you ever find out what was causing the problem with your car? I appear to be having the same ticking sound with my car. I have the same rotary dial set up as you.

any help is very much appreciated.

Thanks,

Rob

Help!

I've got UK 1996 E38. Unfortunately UK cars are way below spec than US cars - my air-con controls are analogue and manual (four dials - left heat, air flow control, fan speed, right heat) plus three buttons to the left of the dials (air con on, air circulation, rear window demister). The air-con control that you guys got in the states with the pixel display (with the notorious pixel failures) wasn't fitted to our cars till about 1997.

Suddenly last night all the air con functions stopped working - I can't change the air direction or temperature, and the air con, recirc air and rear window demister buttons aren't working either. I can however turn the blower on and off and adjust it's speed. In addition I've noticed a ticking from the engine compartment, at the rear by the bulkhead, it's some kind of heater valve fed with coolant form the engine. It was red hot this morning and still ticking (must have been going all night) so i've disconnected it. This tick happens every three seconds or so, even when the engine is switched off / no key in the ignition. My guess is that a stepper motor has got stuck and has blown a fuse or something. Anyone have any ideas? Whilst I'm on it, I've never been able to get warm air out of the vent in the rear of the front armrest (for rear passengers) - only cool air. Can anyone help??

PS I've attached my "paint" image of the controls to avoid any confusion - sorry it's poor but it gives you the general idea!!

[foggy]

Hi Rob

I found a link on the web regarding the problem - it traced it to the "hot water valave" in the engine compartment - lift the bonnet, at the rear of the engine (on the bulkhead) on the right hand side is basically the valve for the heat exchanger. I've still got the print-out in my service history - it's www.laczik.org/BMW/repair/E38_AC/E38_AC.html
I've checked and the link is still live. it doesn't show our controls (the rotary dials) but the rest is spot on.
With regards to my problem - it resolved itself! I went on holiday to Thailand for four weeks, and when i came back the car battery was totally dead - it may even have been something to do with the valve constantly opening and closing. I jump started the car - and the air-con jumped back into life after three months of no air-con !!!!!
Evidently either a sensor reset or whatever was stuck became unstuck. I would certainly suggest the first thing I would do in the same position again is consider disconnecting the battery and leaving it for a few days if possible prior to re-connecting it - maybe this would have the same effect? Otherwise the link above should prove helpful.

Best of luck with this - hope you have the same luck as I did!

Regards,

Foggy

[foggy]

PS forgot to mention - if you follow the link I sent you, if you disconnect the electrical connector on the left hand side of the valve it stops the clicking - but I did this for a while and it didn't remedy the problem - just stopped the clicking.... if the component is knackered I guess you could always pick one up at a breakers? try www.fabdirect.com - really helpful!

[RLM]

Hi foggy,

I actually unplugged the thing last night to confirm that it was the cause and it was. I cleaned the contacts then plugged it back in and all was right with the world. AC, Defogger, and recirc. It did start to go back to ticking a bit, but then I liberally applied contact cleaner and all seems much better. Hopefully the fix lasts and it is only the contacts as opposed to the valve that needs to be replaced.

thanks again,

Rob

Hi Rob

I found a link on the web regarding the problem - it traced it to the "hot water valave" in the engine compartment - lift the bonnet, at the rear of the engine (on the bulkhead) on the right hand side is basically the valve for the heat exchanger. I've still got the print-out in my service history - it's www.laczik.org/BMW/repair/E38_AC/E38_AC.html
I've checked and the link is still live. it doesn't show our controls (the rotary dials) but the rest is spot on.
With regards to my problem - it resolved itself! I went on holiday to Thailand for four weeks, and when i came back the car battery was totally dead - it may even have been something to do with the valve constantly opening and closing. I jump started the car - and the air-con jumped back into life after three months of no air-con !!!!!
Evidently either a sensor reset or whatever was stuck became unstuck. I would certainly suggest the first thing I would do in the same position again is consider disconnecting the battery and leaving it for a few days if possible prior to re-connecting it - maybe this would have the same effect? Otherwise the link above should prove helpful.

Best of luck with this - hope you have the same luck as I did!

Regards,

Foggy