non-working auxillary fan
 

The auxillary fan on my 1992 190e 2.6 is not turning on as it has in the past. Gets real hot here in Texas. Any ideas for me? Also, I do have the mb 201 service manuel library cd, can't seem to find any help for this anywhere. I do know where the aux fan switch is located, is it best to replace this first and go from there?

Have you determined if the aux fan spins freely and if so works if you supply direct voltage?

Check the fuse, I found that the one on the 300D was shot while troubleshooting a malfuctioning headlight. In fact, if you have not done so, I suggest replaced all the fuses, they corrode and loose contact.

I'm not sure right off the top of my head what type of switch the 190 has, could be a simple thermoswitch on the thermostat housing or a "combination" "switch" via the engine coolant temp sensor (do a search, I believe you pull the temp sensor wires and the fan comes on).

Should be a relay, too.

And make sure the fan turns, the bearings can sieze on them.

Peter