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Eric, Automotive Repair Shop Manager
Category: Ford
Satisfied Customers: 31934
Experience:  Automotive Repair Shop Manager, Technician
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I have a 2003 f250 6.8l. The a/c clutch will not engage in

Customer Question

I have a 2003 f250 6.8l. The a/c clutch will not engage in normal operation. Have checked fuse,voltage at high & low switches (ok)also did a jumper at both.checked relay (ok).then pulled a/c relay did a jumper .doing this made the clutch engage a/c blew cold air.
Submitted: 1 year ago.
Category: Ford
Expert:  Eric replied 1 year ago.
I am sorry that you have not been helped yet. I just came online and saw your question.
Ok, the relay should be labeled for its pins tell me which corresponding cavities in the relay box you jumpered to get the compressor working.
Also, with key on and ac on, check voltage at all 4 cavities and tell me what they are.
If no labeling on the relay, it should be
86 30
85 87
Customer: replied 1 year ago.
With relay pulled ,selector switch at max,key on.
30 -- 12.06 v
86--- .011 v
87--- .01 v
85 --- 12.00 v
Can here click at compressor with Jumper at 85 to 87 and 30 to 87
Customer: replied 1 year ago.
Had 85 & 86 wrong on my note pad..
Corrected below
30 - 12.06
86-- 12.00
87-- .01
85-- .011Can here click at 86 to 87 and 30 to 87
Expert:  Eric replied 1 year ago.


Ok, pin 85 is signal from the pcm connect C175, pin 69, pink with yellow striped wire. You will need to check for power at this pin on the pcm. If power is there, then a break in the wire between the pcm and the relay. If no power, then we will need to go from there

Customer: replied 1 year ago.
Don't have wiring diagrams and is the pic between battery and blower casing under hood
Customer: replied 1 year ago.
Can you tell me where the powertrain control module is mounted on this truck
Expert:  Eric replied 1 year ago.
Sorry for the delay. My computer crashed and I still cant bring up my repair manuals software program.
I do know that the pcm is at the left side of the firewall in the engine compartment, near where the left inner fender meets the firewall
For right now, I am going to opt out and see if another expert can pick up from here, at least until I can get my software working in case more wiring schematics is needed.
Customer: replied 1 year ago.
The 2x5 small box I see ,has a 8 wire plug and a cable to throttle assembly
Customer: replied 1 year ago.
But this box has no pink/yellow strip wire in the set of 8