Aux Cooling Fans- 1995 SL 500
 

My electric Aux. cooling fans are not working. I tested the fans using an outside 12 volt source and the fans themselves work just fine. I tested the CTS sensor with an ohm meter. My info states that the resistance should equal 310 ohms at 100 degrees (C) for the fans to begin their low speed operation. The fans should fully operate at 200 ohm at 115 degrees (C).

My CTS specs are a bit off, but at 120 degrees (C), the sensor is reading 240 ohms. That should have signaled the fans to run since they do operate at any resistance less than 310 ohms. Even at that temperature and resistance, the fans still won't operate. (Even with the A/C on.)

What am I missing here? The fuses are good and the fans themselves are good. Is there a fan relay buried somewhere in the system that has malfunctioned? Is the computer that controls the thing bad? I also saw a listing for a part called a "Aux Fan Resistor". Can any body tell me where that is located?

Thanks

On my 97 SL there is a ceramic resister mounted in between the fans, it is white. I don't know if yours is there, but mine is. Good luck!
Happy Benzing
Brian

Thanks for the info on the resister. I haven't had time yet to dig into it, but there does appear to be a white resistor like item mounted to the inside of the grill between the fans. I'll check that out.

aux cooling fans
 

I do not remember exactly, but I did a search on here and found it when I had the problem. There is a relay with a fuse under the fuse box. Dairel

Thanks Dairel. The white resistor listed in the other post didn't solve the problem. I'll see if I can locate the relay in the morning.

Thanks again!