[shadowfax]

At first I was afraid my AC was failing but then realized it was only while stuck in bad traffic. Apparently, my car is a lot smarter than me and was turning off the AC when getting too hot. Eventually iDrive said, "Drive moderately to cool engine. If temperature increases again, consult service center." Just as I arrived at my destination it said, "Turn off engine and allow to cool. Do not open hood, scalding hazard. Please call Roadside Assistance." Six minutes after that water was 253F and oil 251F.

After it cooled down the coolant level was fine and the car wasn't throwing any codes. Cooling fan doesn't seem to want to start. It looks like it is about to start and then appears to want to turn backwards but never starts. Drove home (93 miles) late at night to avoid traffic, with the heater on high, and turning it off at red lights and it didn't overheat again.

The 4 fuses next to the fan icon on the fuse diagram were all fine. Best case scenario would be a bad relay (130A). I asked around and was told that with a wiring diagram I can check the input power and ground (primary switching side) and then the output side power to the fan to see if the relay is bad. However, after a long weekend I'm not fully understanding that.

[MarcoZandrini]

The first step in diagnosing a problem is the scan the car's electroinx for codes. Find a reputable indie shop that specializes in bimmers in your area at www.bimrs.org.

[shadowfax]

Originally Posted by MarcoZandrini

The first step in diagnosing a problem is the scan the car's electroinx for codes. Find a reputable indie shop that specializes in bimmers in your area at www.bimrs.org.

I was fortunate enough to be camping next to a group of mechanics from a great indie shop that only works on bimmers, and one of them had a scanner but it showed no codes. He did recommend keeping a code scanner in the vehicle at all times just in case, and I plan on heeding that advice.

Are you saying that a bad relay would show a code? I didn't consider that. I think I was over-optimistically hoping it would be the inexpensive relay and not the somewhat pricey cooling fan assembly.

[dradernh]

Originally Posted by shadowfax

I was fortunate enough to be camping next to a group of mechanics from a great indie shop that only works on bimmers, and one of them had a scanner but it showed no codes. He did recommend keeping a code scanner in the vehicle at all times just in case, and I plan on heeding that advice.

Did the mechanic happen to suggest which scanner would be a good one to get?

[shadowfax]

Originally Posted by dradernh

Did the mechanic happen to suggest which scanner would be a good one to get?

No, and I can't recall the brand but I received an Innova 3040RS last Christmas and they both seemed to have similar features.