1979 300SD approx. 160,000 miles living in New York City. I recently replaced my blower motor after it finally died. All was good for about 2 weeks. All functions were working as they should. One day I went for defrost and the fuse blew (#3 in the fuse box, 25amp). No problem I replace the fuse and all is good again. A few days later the fuse blows again. Now the second I hit any button on the control panel the fuse pops. I cleaned the contacts on the #3 slot but still the fuse is blowing. When I installed the blower motor I did use my old cage. I don't understand what is causing my problem? The situation just got worse over time and I don't understand why. My next move is to go back and look at the blower motor itself. The install was a simple procedure of 3 bolts and 1 plug. I don't think I could have wired wrong even if I tried due to the plug. Anybody have any ideas? I even went so far as to have my buddy put his ear below the glove box so he could listen while I pressed the control panel. He said the motor ran for about 1 second with no strange noises then or course the fuse blew. On the install I did have to cut one bolt as it was stripped. Now the blower motor is held in place with 2 bolts instead of 3. I am using fuses that have what I think is copper. Some of my old fuses already in the fuse box are silver in color. Does this matter?

NYDIESEL,

Sounds like a short somewhere, possible in the fan motor.

Disconnect the fan motor and see if the fuse blows. If it does, there is a short somewhere in the wiring.

If the fuse does not blow with the fan motor disconnected, It appears that the motor is bad.

Try connecting the fan motor directly to the battery and see what it does. Any noticeable smoke or overheating suggests the motor is bad.

P E H

Most likely shorted A/C low presure switch. Most common casue of what people believe to be a faulty servo....Robert

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership