Blower fan fuse keep blowing and AC keep cutting out - PeachParts Mercedes-Benz Forum

pexcellence · #1 08-14-2006, 02:43 PM

I have a 86 420sel that keep on blowing the blower fan fuse. I replaced the blower fan motor with a new unit. It does this when the fan is on high. Also, I've been having problem with the AC cutting out. I tracked it to problem with the push button unit. There is no ground signal. Can there be high resistance in the PBU causing the fuse to blow and the AC to work intermittently?

Thanks,

John

dpetryk · #2 08-14-2006, 06:38 PM

Check the compressor clutch electromagnet. These things short out and draw enough current to blow the fuse. A bad electromagnet will cause both of the symptoms you describe.

pexcellence · #3 08-16-2006, 04:58 PM

I did degrease the clutch and check the gap a while back. What else do I have to do?

John

dpetryk · #4 08-17-2006, 06:35 AM

I would apply 12 volts to the coil and measure the current. If it is drawing too much, replace it. I think about 3 amps is normal.

pexcellence · #5 08-17-2006, 10:48 AM

Newbie to MBZ.

Thanks,

John

dpetryk · #6 08-17-2006, 11:16 AM

There is a wire that connects to the compressor near the pulley. Put an ammeter in series with this connection and measure the current there. The coil I am refering to is underneath the pulley. You cannot see it unless you remove the clutch assembly from the compressor.