AUX FAN ISSUES HELP!!!!!!!My

[peeweeherman]

Ok, so I know that E36 has had some issues with the aux. fan infront of the radiator, but I have an E46 and the fan is stuck on TURBO and goes until it drains the battery. I got a 2000 328i and I called the dealership and they always give me the same answer.."they are bulletproof" or "hmm never heard of that happening" but that seems to be their answer for everything. They really are no help, and really I just wanted to know if anyone has experienced this problem with their car? Is it just a rare thing, or has BMW's E46 got similar problems like the E36 has had problems with the fans blowing out of control? From what I can understand there are about 3 relays or sensors where my fan could be screwing up, but if anyone else has had this problem your input would be a lot of help. If anyone has any info besides just bring it to the dealer that would be great. Thanks

[Kassel]

thats weird, I know my aux fan stopped working towards the end of summer, and i never noticed, eventually the coolant heated up and the cap broke... never heard about it spinning too fast though

[tdc]

Sounds like a thermostat problem. I recall a bunch of cars from that year having an issue with them.

Some had fans that wouldn't shut off and others had fans that would never turn on.

[peeweeherman]

Yeah, I took it to the dealer and they got a new 525i, and also a 330i with the same problem this week (weird) that just had the same problem I am having. The fan runs until the car has no more juice. Right now I have to get out and pop the hood and unplug the fan when I park, It's lame but the battery stays alive, than I plug it back in before I start the car. I already blew my coolant expansion tank as a result of this mess, but I got that fixed. I am not too good with electronics so I will leave it up to the big boys at BMW to solve this one. I was just hoping for a common problem so I could maybe save some money on the diagnostic when they search for the problem. It's worth a try

[kvcicca]

This sounds like you need a new fan to me. It has power at all times, and is signaled on by the DME, so it is either shorted out internally, or something is wrong with the signal wire from the DME. I have never seen this happen either on an E46. A good way to test if it is the fan, is to disconnet the fan, and jump the wires from the connector to the fan, but do not jump over the small signal wire. In other words take 2 straight pieces of wire and connect the red/blue wire to the proper pin on the fan, and the big brown wire to the proper pin on the fan. If the fan comes on, it is junk.

And in the mean time, there are 2 large 50amp fuses in the glovebox. I think the one on the left is the one for the aux fan but i'm not sure (you'll have to test). Figured you might want to pull this instead of unplugging it all the time.

[TG328TG]

im confused....why dont you just let the dealer fix it?
there is a common problem called "final stage" but it is for the internal fan only blowing full speed, doesnt have any affect on the external fan

[kvcicca]

I saw the 1st E46 I have ever seen do this today.

New fan fixed it.