1999 E46 323i (manual) primary electric cooling fan doesn't shut off

[monsterkovell]

Turned off engine after comming home and primary electric cooling fan does not shut off - stays on at high speed (4 hours and counting). Pulled out connector to save battery.

What is the reason for the issue? Is it easily fixable by a home mechanic with very basic skills? What are possible options short of taking car to the pros?

This is my ONLY car (for work and pleasure). Any help appreciated.

[dwanders280]

I am having the same problem on my wife's 99 328i. After checking several bboards and calling around it appears the issue is in the control module on the fan. The only way to fix it is to replace the fan. I have ordered everything(I am going ahead and completing an inspection 2 while I have it apart). We drove the car for a couple of days without the fan with no issues. Just watch the temp gauge and plug it back in if you need to while you are driving it. The plug is on the left side of the fan facing the engine. We also had an issue with the radiator fill tank cracking and leaking water. It had to be parked once that occurred. I don't believe this is all related but it may be.

[monsterkovell]

You were right. Repacing the entire fan assembly (which is a piece of cake) was the solution.

Earlier (last December) I had coolant leak out of a cracked coolant expansion tank (aka radiator fill tank). That and the "suspect" thermostat, radiator, and water pump were also replaced during the same visit to the dealer (no longer under warranty).

Funny thing about the temp gage: from day one once it is at normal temp (straight up dead center) it never moves....ever. Once under warranty it moved (more like instantly snapped) from top dead center into the red = overheat light on, the works. It was OK drive after I pulled over and shut down to cool off. The dealer said it was a stuck thermostat. Who knows what else was affected down the road though (see paragraph #2 for possible victims).

I feel that all this stuff is related but hard to prove.

[ranger822]

Well, same problem on my 99 328i ... isolated to the control module on fan. First, given my lack of experience I would have to say pulling the fan wan't quite a piece of cake for me. The age of the car and the brittleness of parts makes removal of the front bumber a bit difficult. Also, the Bentley manual has a few errors or what I would call omissions - such as arrows not showing ALL the right locations for things. Also, the point about the rivet-screws, well I well be darned if I could get all six of those removed- only one came off in one piece the rest were destroyed . . surely a better method could be engineered for this simple and inexpensive part.

The control module on the fan can be further disassembled, removed and the clear rubber componet facing removed - - I am now in the process of checking what part failed on the circuit board. It seems ridiculous that the entire fan assembly and shroud must be replaced just for the control module, especially give the high cost for the entire assembly. Hopefully, my diagnostics on the circuit board will reveal a simple failure that can be replaced by something off-the-shelf perhaps at Radio-Shack otherwise I guess I will have to bite the bullet and go the expensive route.