AUX Fan not coming on low speed via A/C Switch

[Julien]

Hey y'all

I've been trying to get my aux fan working properly on my 88 325i. So far I can it to work when I jumper either relay (low or high speed) which rules out any resistor issues. It will also come on high speed when I jumper two pins by the thermoswitch on the radiator. However low speed via thermoswitch or A/C button inside car won't kick the fan on low speed. I'm pretty sure I swapped relays when I was testing them.

Before I spend any time digging into this in my bentley I wanted to ask if someone knew what could be wrong off the top of their heads.

Thanks!
Julien

[e30vert]

Bentley wont help you. You need the ETM for your year and make vehicle. It will provide you all the wiring paths and wire gauges ,etc so that you can "trace" the circuit. Personally I think jlieve is the boss with regards to issues like this. Well composed replies and troubleshooting seems to really be his strong suit. Im a fan -no homo.

Here is an online link to all the ETM's. Grab one for your year and make and check it out.

http://wedophones.com/BMWManualsLead.htm

[Julien]

exactly what I needed, thanks!

[Quinthirty]

Check the fuses first. IIRC, its #10 for the low speed.

[jeffnhiscars]

I don't think jumping your relays rules out a resister issue. Check your fuses then jump the resistor before you carry on. Te Bentley also has some good diagnostics for this