Blowing fuses

[BIGPAPPA55]

I have an 83' 300D that keeps blowing the blower motor fuse out whenever I put on anything but outside air. I.E. Defroster/A/C/Heat. It will run for about a minute or so than blow. It will not blow if I only use the outside air button.
I have recently replaced the thermostat, and the guts of the monovalve, because of other issues. If I just want outside air it's fine but I would like my A/c coming into the warm months. Any solutions?

[SD Blue]

Your description seems to be pointing at the Automatic Climate Control Unit or possibly one of the little servo switches, on the RH side of the console, that controls fresh/recirc. vacuum.

Is there any movement at all from the fresh/recirc. door? (in the glove box there is an oval shaped plastic plug that you can pull to check for movement)

[dougmcp]

My guess is that your A/C compressor is going south. I say this because that's what mine did both times the compressor went out. Bummer.

[Ramblin]

I am not trying to contradict what has been said so far but if a fuse blows it means the device is drawing too much current and the device is probably defective is some way..As far as blower motor go it ususally means the bearings are bad and it is dragging for some reason...Or that there is something lodged in there that is dragging it down....I would pull the blower motor and inspect it for defects...my 2cents

[michakaveli]

We had the same on our '82 300D. The blower motor was shot. The commutor was well worn, almost no copper left, surprised it was even working. I bet that's the problem

[dougmcp]

On my car 300SD the blower motor and A/C compressor are on the the same fuse. Mine would run for awhile and pow, no fuse. Indications to me say that if the fan works on air only and as soon as you turn on heat, A/C or defrost the A/C compressor comes into play and takes the fuse out. I will defer to the guys with the 300D's who know the specific model better. I hope they are correct, it's a lot less expensive.

[BIGPAPPA55]

Thank you all for your input and suggestions, but the preplexing thing is that it works fine with the EC button on with the climate control on, it cycles on and off, properly regulates heat and runs fine just using the fan speed buttons. Its just when I push any of the other buttons that the fuse will blow, thats why I don't think its the blower motor.

[dougmcp]

The EC button is the only one that doesn't use the A/C compressor, all the rest of the buttons the compressor is on for heat, air and dehumidified defoster. Go back to my first post, sorry to say, I'm still thinking the compressor is done.