I have a 98 S320 with 119k and an electrical problem. Fuse #21 "heating wipe/wash system, outside mirror, tr. oil cooler, automatic climate control" keeps blowing. any suggestion would be welcomed. BTW the mirrors still work and the climate control still works with the fuse blown.

Thanks!!

what does not work when this fuse blows? How did you come to know it was blowing?

My battery has been dying after 3 days of the car sitting and I was trying to isolate with a amp meter connected to neg battery cable and i found this blown fuse. It blows everytime i replace it (after i turn the car back on). I think this is connected to my battery problem, so I want to solve this first and it may fix the other. As for what doesnt work I am not sure. How could I test the wiper fluid heater?

the wiper fluid heater might be popping the fuse, disconnect the electrical lead to it and see if the fuse holds when the ignition is turned on.. What is the current draw with the ignition off? Since the battery is draining fairly rapidly, I think you may have two problems.

but I only have documentation for W210 cars. I think that rather than powering the movement of the outside mirrors, your fuse #21 supplies current for the heated function of them. With ignition off, can you measure the current drain from the battery and then pull fuse #21 without turning on the ignition. It would be good to know if the drain changes. As far as the heated windshield fluid goes, I think that the car may circulate coolant thru the reservoir and that there is some kind of thermo switch that is involved with this. My guess would be that the electrical coolant pump that supports the REST function on HVAC system is also fed by fuse #21.