1995 F53 AC fuse blows in drive

[boblouder]

I have a 1995 Newmar Mountain Aire on a Ford F53 chassis. I have a fuse inline going to the compressor. When I start the engine and turn on the AC, it blows cold as long as I am in Park. The minute I shift into gear, the wire starts to warm up until the fuse blows. Looking at the schematic, the PCM is wired into the power line at the positive side of the diode. The PCM would be the only thing affected by the shift into gear. Therefore, the short must be coming from the PCM.

I wanted to know if anyone had any thoughts on this matter. Is there any other possibilities? How would you deal with it? I appreciate any responses.

[subford]

The wire going to the PCM is only to tell it the AC compressor is engaged.
I would not think the PCM would be your problem but you could cut the wire going to the PCM to make sure before spending $400.00 at a salvage yard for one.

Do not know what wiring diagram you are looking at so I will post one so that we are on the same page:


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[boblouder]

Thanks for the reply. The diagram is exactly what I used. I thought I read somewhere that the PCM also told the compressor to shut down when the vehicle was going up a hill. I hate to unbundle all of the wires. Is there an easy way to get to the PCM wire. BTW, where are the PCM modules usually located?

[subford]

Originally Posted by boblouder

I thought I read somewhere that the PCM also told the compressor to shut down when the vehicle was going up a hill.

This is true for some small engine vehicles but not for the 460 in the F53.

Originally Posted by boblouder

I hate to unbundle all of the wires. Is there an easy way to get to the PCM wire.

The 348 P wire is located in front of the radiator at the low pressure switch.
The 883 PK/LB wire only goes through one plug (C120), the engine plug on its way to the PCM computer.

Originally Posted by boblouder

BTW, where are the PCM modules usually located?

It is located at the LH side of safety wall, see Image below. But some home builders have a panel in front of it so you can not see it.


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