The A/C quit working (fan functions normaly) on my motorhome recently, it had been very cold up to that point. I applied 12volts at the low pressure switch (contacts were closed) and compressor engaged, system cooled. Took it to my mechanic and was told the ECM was bad. Is this possible?

I have a wiring diagram for the F53 chassis and can see there is a connection. Are there mauals available that tell what processes take place at each pin P/N F6TF 12A650 AJA.


Thanks,
Mike Layton

 

I recently checked out the AC wiring for my 2001 F250, because I want to put in a cut-out switch to turn off the AC compressor when defrost is on...

There is a connection to the ECM as a SENSE input so it knows when the AC is on - but I also think there is a cut-off so when you are under high load it will turn off the AC compressor.

If you wanted to, you could circumvent that function and not have to replace the ECM - if that's what the problem is.

Could just be the relay is bad where the PCM tells the system to cutoff under load - can you post a pic of the schematic?

 

Thanks for responding. I only have the Ford chassis wiring diagram. I stops at the body builder accessory feed plug. I think there may be a relay between the dash controls and this plug. Next step may be to trace back the Ford wiring & cut open the coach builders wiring bundle.

 

Found the problem. Kept hearing my grandpa's voice in my head " it's probly sum'n simple". Anti icing thermostat would not close. Jumped around it with everything else in circuit. Air will frost you're umm, eyebrows. Now I need to find a replacement Denso #AA113550-1200 thermostat.
Thanks for the input.
Mike

 

Thanks for reporting back