Auxiliary Fan Relay
 

My aux fan isn't coming on when the engine is hot or at idle, so I removed and grounded the wire attached to the temp switch while the car was running. The fan then worked.

Through the details in my Chilton guide, it then says to replace the fan relay. Problem is, I don't know which one is the fan relay (neither does the dealership). I believe it sits under the driver's side dash/steering wheel, but I have no part number guide to help me. Does anyone know where I can get a new or refurbished fan relay (or any relay, really) for this old beast ?


AARON ROCHARD

1976 230.4 W115

There is a procedure for testing the fan switch. I don't know if it is by pulling the ground. But if worst comes to worst: when the fan is running, pull the relays, one by one until the fan stops. This will identify the right relay. There is amateur advice for you.

Steve
'85 500SL Euro

Thanks, I'm almostsure it's the relay now, however, the dealer says he can't (according to his computer) tell which one is the aux fan relay. All I know is that it is a 5 pin relay. Does anyone out there know the exact part number for this "dealer only" part ?

Thanks,

AARON ROCHARD

1976 230.4 W115

Take the number right off the part!
 

I don’t know where they are on your car but someone with the manual or CD should be able to tell you approximately where they are. Then you can pull them until you find out which one it is. My dealer told me to do just that, as they couldn’t say which one in the bank of relays was the offender. Mine are in behind the right side passenger foot panel. Good luck.

Steve

Not the same subject, but I like to know how to ground the aux fan to ON position when the A/C is turn on. My car is 75-240D.

jack