My car is a 2001 330Ci - 5 speed with about 90Kmiles. On Saturday while waiting for my autocross run in Bowie the temperature indicator all of a sudden went up beyond the middle and kept going until I turned the engine down. I then turned my car on right before my run and during my run the temperature actually went down and got back to the middle. After my run I pulled over and it seemed that my electric fan didn't turn on as it should've been so instead of waiting in line for my next run I just waited on the side and shut down the engine. I only turned the engine on right before my run and sure enough during my run the temperature actually went down because of the air flowing from the front of the car. On my way home after the event I was lucky there was no traffic so I cruised home and with the air flowing from the front of the car I was able to get home safely. I checked the fuse and it was ok, I was told to also check the relay for the electric fan but I couldn't find where it was.

Yesterday, I drove the car for a little bit and let the car idle for a while and somehow the electric fan kicked in. I don't drive the car daily anymore so today after work I drove the car for a little bit and let the car idle for a while again just to make sure and sure enough the electric fan didn't kick in and the temperature kept going up past the middle until I shut the engine down.

In short, my electric fan sometime working sometime dead.
- Is it a sign of a bad electric fan or just bad relay? Where can I find this relay and how do I test it?
- Should I try to replace the coolant temperature sensor in the lower radiator hose first before changing the electric fan?
- If it's the electric fan from what people told me and looking at the Bentley Manual it should be very easy for E46 non-M with stick shift, is this accurate?

Thanks for the info guys.