Hi,
The car is a 1989 190E 2.6 from California.

Here's the question;

All my freon was gone due (it turned out) to a defective, leaking schrader valve.

When the A/C shop was filling it they pointed out that my aux fans should run when the air is on. So he referred me to another independent MB specialist. Off I went and he said that my pre-resistor was shot. As a temp measure he pulled the plug of the coolant temp sensor under the edge of the air-filter box, which makes the fans run on high all the time. I drove it home and got a pre-resistor this morning.

The pre-resistor lives down beside the receiver-drier on my car and is a ceramic-type thing about 4 inches long and one inch swuare on the ends. There are two connectors with one wire apiece.

When I put the new one in place and ran the engine, everything works as advertised. The fans come on low with the air and hum away nicely.

After a few minutes I noticed a strange smell which I traced to the new pre-resistor. The I touched the thing and just about screamed. It was red-hot to the touch. Is this usual? If not, what could be causing it to heat up like this????

I'd appreciate any answers asap as I am afraid to run the car with this issue. I don't want a fire!!

Thanks

Jim