radiator fan

[vwtourbus]

I have a 92 735i that I have converted the ac to r134 and my high speed fan wont come on. When its hot out, at idle, the ac will shut off because of high ac pressure due to the high speed not working. The fan comes on low speed but not high. Is the problem the fan or the high pressure switch. Also do I have to evacuate the ac system to change the high pressure switch?

[Bear]

You can check pressures, but I would guess the AUX fan switch (located on your car, I believe,in the upper portion of the radiator, passenger side) may be bad.

[vwtourbus]

Wouldnt the high pressure switch over ride the thermal switch on the radiator if the ac pressure rises too high? Are the fans wired from the relays through the thermal switch? Or could the high speed relay be inop? Sorry for all the Q's but i want to figure this out and BMW are very different than VW that Im used too.

[Bear]

Fans are wired through the relays but directly connected if the AC is engaged, the switch determines fan speed (hi/lo). I sent you a private message and if you respond you will have the BMW ETM (I hope).

[Bear]

BMWE38.Org - The 95-01 BMW 7 Series Owners Reference
Everything you want to know and more.

[Bear]

make it e38.org BMW 7-series information and links

[vwtourbus]

Thanks for the info. Ill check it out but right now I have to figure out why my rear defrost doesnt work.

[AlpineSixAndSeven]

^ lol that sucks... does the button work show power?

[vwtourbus]

Yup, an fuses are good. Im thinking a relay is not working because the switch works and the light in the switch vomes on just now poer to the rear window. I read some where the control module for the heating and ac behind the sword may have something to do with it.