Electric fan problems - BMW Forum

madsat · 08-21-2009, 10:59 AM

Hello everyone,

I'm in need of advice as I would rather try to fix the car myself before taking it to the dealer and getting all my money sucked out of me.
For the last 2 weeks I noticed that my ac was working a bit intermittently although it was still blowing cold air, just not all the time. Then one evening driving back home I noticed that my water temperature was in the red. I stopped as soon as I saw it but I already had a crack somewhere and was loosing my coolant. We pulled it back home (lucky me I was only a few blocks away) and noticed that a plug on top of the fan was disconnected and there was a crack in the expansion tank. I've since then replaced the expansion tank and replugged the wire but the fan still won't start anymore and there is another small crack on the top hose going to the expansion tank.
I've read that the final stage unit could cause the ac to do what it was going but would that cause my fan not to kick on? is there another relay somewhere? I've checked the fuses in the glove compartment but didn't see anything bad.
Any help appreciated!

darkhorse737 · 08-21-2009, 11:11 AM

year of your car?

model?

your auxiliary fan... how many wires at the fan terminal?

how is your skill/s in electrics?

madsat · 08-21-2009, 11:16 AM

Quote:

Originally Posted by darkhorse737

year of your car?

model?

your auxiliary fan... how many wires at the fan terminal?

how is your skill/s in electrics?

Sorry it is a 2000 323i. If the fan terminal is the box on the passenger side of the fan, it has 3 wires. I'm in no way an electrician but did just replace the wiring harness in my 64 pontiac tempest so if it makes sense I can do it.

darkhorse737 · 08-21-2009, 02:32 PM

For your car, the auxiliary fan is controlled by the ECU. There are no relays in between.

A/C intermittent operation may be because you are low on refrigerant.

aux fan operation: you will have to check that with A/C of. If car left at high idle(say 1500rpm) on a warm day, the aux fan should come on jst as teh temp guage rises past the halfway mark.

if it doesn't, either the fan is bad or the temp switch has failed.

Cheers

madsat · 08-21-2009, 03:45 PM

I had checked the fuses but recheked and switched them around and the fan turns on now as soon as the a/c works. I tested the fuses and they all light up, I'm now totally confused...
When the incident first happen we noticed that the plug on top of the fan was disconnected (the car was at BMW in february where they changed the belts), what is the plug for? could it cause a short?
thanks for your help!

darkhorse737 · 08-21-2009, 04:15 PM

Quote:

Originally Posted by madsat

I had checked the fuses but recheked and switched them around and the fan turns on now as soon as the a/c works. I tested the fuses and they all light up, I'm now totally confused...
When the incident first happen we noticed that the plug on top of the fan was disconnected (the car was at BMW in february where they changed the belts), what is the plug for? could it cause a short?
thanks for your help!

glad the fan now works...

i don't know for sure what plug u mean... but to my mind, if there are no connectors visible in the place where that plug is, then in most likelihood, it is a dust cap. or a peephole to check operation.

i sorry i couldn't be of more assistance. pics could help. If it is indeed a dust cap... covering it with some tape will solve that prob.