1991 318is aux fan problem

[dtrmend]

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Sorry for the duplicate post but I was confussed on what I should use as a title.

Hello, I am a Newbie. I have a 1991 318is. My problem is I cannot get the auxiliary fan to come on and my car is getting critically hot. I have jumpererd the fan and it does work. However, I cannot get it to engage on its own. Please if any body would be so kind as to offer me some possible solutions. I apologues if I have not followed proper protocol but I have read and searched the threads trying to find out if my question has been asked and answered. I had no luck. Therefore, here goes thank you in advance for any help

[nicko]

Hi I am not an expert, but in general, I would check the fuse first, than check if you have a bad relay, also if there is a resistor on fan sometimes they die. Also the switch itself in the car may be bad.

Try and find a wiring diagram for your car and trace the power.

Hope this helps

Nick

[Pirate_copy]

i think they are viscous fans and they can fail after around 100,000 miles.

Not sure how this helps to be honest, but it is a common problem (or so i am told). i had to replace it on my old Bimmer

[dtrmend]

thanks to both of you. Its a starting point

[BMWredneck]

Another idea would be replacing the aux fan coolant temp switch. its cost about 36.00 plus shipping if you get it from Bavarian Autosports www.bavauto.com They have helped me with many issues and are very prompt about deliveries. The also have tech support which can also be useful.