MCR

Sorry if I'm being a pest guys, but I seem to be having a most unusual issue with my car over heating due to the cooling fan not running under ANY circumstances.

The car over heated in hot TX weather and I shut it down quickly. When I noticed the cooling fan not working I searched here on the boards reading everything possible related to the subject and I cannot find a solution. From what I understand, activation of the max AC setting should turn the fan on. Seeing that doing this does not turn on the fan, I also tried unplugging the lower temp sensor which I read shoud default the fan to the high speed.... it does nothing. So figuring the fan itself must be toast, I installed a new fan and still have the existing issue.

Other things.... the fan harness has good power and ground, but I am unable 'like many' to do any testing of the signal wire not having proper equipment. I also pulled every single fuse and all were good. I even checked the AC charge and all is well. I simply cannot figure out what is causing my AC and Cooling FAN to not run. Im guessing the AC compressor isnt coming on because the fan isn't turning on? The car is throwing NO codes via obd2.

Any help would be great appreciated!

2004 545i with 75k miles.

MCR

Sorry for the double e post...

Is there any way to eliminate either of the two temp sensors for testing purposes, and could a bad thermostat cause this?

MCR

Dont ask me how moisture got into this ONE plug but...... bam! The signal wire for the fan came off with the connector (top row 4th from the left)... the rest look ok.

jtbgonesailing

Check the drains for the compartment air filters. There are 2 drains associated to each side. On the outboard side of each filter tray base, there is a drain that enters the finders. Below each filter traffic base on each side is a additional drain. If these drains become clogged with leaves and other matter, the results will be water in the e-box and water entering the passenger compartment through the hvac outside air pickup.

Hope those contacts cleanup for you and you are able to get the male and female pins you will need from a BMW dealer. There cheap enough to pickup locally.

Good luck and keep us posted with your progress.

MCR

I dont think the male post on the module is removable.... I was able to get the back cover off, but cannot remove the circuit board to gain access behind the pin.

MCR

Can anyone confirm this ecu also controls the ABS hydro unit? I cleaned up the connections and put it back together until I can have the pin fixed, and now I have what the Land Rover community calls the 'three omigos' where you have a brake light, abs light, and stability control light. It looks like the same color combination wires are coming off the hydro unit and going to the same ecu as the fan signal wire.