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kdbarnard · 06-23-2016, 07:21 PM

Would someone have a suggestion where I can get a wiring diagram for the chassis AC on a 2006 Ford F53 chassis.

The compressor clutch does not get energized. The AC clutch relay is good and there is power to the relay but the relay does not energize due to some problem in the relay energizing circuit between the relay and ground.

nothermark · 06-23-2016, 07:29 PM

Poke around here:

https://www.fleet.ford.com/truckbbas...bodybuild.html

kdbarnard · 06-23-2016, 07:57 PM

Thanks nothermark. I have looked and did not find anything helpful before but per your suggestion gave it another look. Only 3 references to a/c in the 2006 F53 document and nothing in others. A real wiring diagram with wire colors etc is what I am needing.

twinboat · 06-23-2016, 08:06 PM

Have you jumped the low pressure switch or checked the low side pressure ?

kdbarnard · 06-23-2016, 09:00 PM

Thanks for your reply twinboat. Yes, one of the first things I tried was to jump the pressure switch and that did not engage the clutch. After that I checked the switch and confirmed it is closed.

I have also supplied power to the A/C compressor clutch via the relay socket confirming the integrity of the clutch circuit. When I run the engine with 12v to the the clutch the A/C blows cold air (50 deg on a 100 deg day).

I have swapped the relay with the horn relay. Horn works with both relays. A/C does not work with either. The pin in the socket that I think should supply the ground to energize the relay has no continuity to ground.

subford · 06-24-2016, 06:12 AM

Here is a 2004 wiring diagram if it would help:

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w2drfg · 06-24-2016, 06:50 AM

Subford
From what you describe it may be the signal out of tge pcm that you are looking at when you do not read a ground. If you put 12v on the gray/white wire on tge compresspr clutch connector and ground on the black wire then the clutch engaged. Is that what you did by applying power? The pin out of the pcm will provide a ground to the relay to apply power to clutch. If you have more diagrams showing what logic sets the pcm then trace that. I have seen the engine temp sensor and radiator fan circuit in the a/c circuit. If the pcm thinks the engine is in overheat condition then it stop the a/c from energizing. You could remove the connector off clutch then turn key on and check for ground on the black wire on connector going to clutch. May have to start engine being careful of dangerous moving parts to check ground.

w2drfg · 06-24-2016, 07:17 AM

If you look at bottom of relay you should see pin numbers. Pin 86 gets ground from pcm switch out pin c175 on diagram. Causes relay to energize then supplies power out pin 87 of relay to gray white wire. Hope that helps.

subford · 06-24-2016, 07:46 AM

Ksmith,

I think that kdbarnard also went here for help so you might want to read this link:
I need chassis AC help on 2006 ford f53 chassis. Its a

w2drfg · 06-25-2016, 08:31 AM

I apologize for sending replies to you subford when I should have been replying to kdbarnard. I need to pay more attention in the future. I do see where he got basically the same info I provided. Thanks for your reply.