I have a 2007 Ford F150 4.6l with manual climate control. The ac hasn't worked since I've had the truck. I vacuumed the system. It held good over night. I recharged it. But the ac compressor never came on. I've got static pressure about 100psi. When I connect the scan tool to it and using for scan I can see these pids for the ac:

73 degrees F-------Aat ambient air tempYes------Acclt_alw ac clutch allowedOff---------Accs ac compressor clutch cycling switchOpen-------Acp Ac pressure switchPsi---------Acp_press ac pressure sensor
1.67v ---------Acp_v ac pressure voltageOff--------wac/accr ac clutchNo fault--------Wac_f wide open throttle a/c cut-off fault

Is this telling me that the cycling switch and /or the pressure switch is bad? I've tested the cycling switch per the service manual and it tests good. I haven't tested the pressure transducer yet. It has just started raining. Hopefully it'll rain for about 24 hrs. After that I'll go back and start more testing.
So far it looks like the cycling switch may be preventing the pcm from commanding the ac to work. It's stopping it from sending ground to the relay which would then power the other part of the relay and send ground to compressor. I'm sometimes wrong so feel free to correct me and I also need some prodding to go the right direction to complete this diagnostic. I've followed the service manual but don't fully trust my results. They are pointing to new PCM needed. I'm leaning to the PO has replaced the instrument cluster with the incorrect one, probably trying to upgrade it to one with a tach. It has it but don't know whether or not it's supposed to. So if it was swapped and the programming wasn't updated to tell the ic the as built data, maybe I need to reprogram it. But I don't have the as built data. It would be gone with the old unit. Anyone know of a way I an get the as built data? Would it be stored within the pcm or only in the old instrument cluster? Would it be possible to maybe find one at the junk yard that has manual temp control that's the same model as mine and it have the data that's needed?

​​​​​​Any idea on which direction I should go next would be welcome and much appreciated.
Thanks in advance for your helpCindy

 

Have you tried jumping the clutch relay contacts on drivers fender to prove compressor and get cooling working ?
I wouldn't doubt that the cluster could be a source of problem -just guessing .
I can tell you that the relay contacts are in opposite corners so it doesnt matter which way you plug relay in . The relay is small and contacts get burnt from the heavy load of clutch .. if you jumper it use a fused jumper at least 20 amp inline . Just to protect wiring if you make a mistake .

I had a drawing of relay but I cant find it , perhaps get number off of it and google it . It doesnt hurt to put a new relay in as the contacts do get burnt . You can cut open the old one and manually push relay to bring on clutch .

 

Your PCM is not seeing a valid signal from the low pressure cycling switch (ACCS). Either that circuit is open and not providing a valid signal to the PCM's input pin or the internal port in the PCM is not working..

There's nothing wring with your pressure transducer. It's reading your static pressure.

Cluster problem? Dunno. Insufficient information right now.

Leave the relay alone for now (unless you want to jumper it to test teh clutch/compressor), your problem is "upstream" from it.

1. Did you scan the PCM for any faults that would inhibit compressor operation?
2. How did you charge the system without the compressor operating? That takes very expensive equipment like they use in the factory. How much refrigerant was installed?
3. Did you check the PID for the AC Request signal from the climate control module (via the cluster)? It should cycle as you turn the A/C on and off.

 

After wiggling some wires and connectors around, my problem has changed. And I believe the problem before was the connector at the control.

the new pids are:



So now the problem is I still don't have power at the compressor. Also if I go back to the relay (which is new) I get power to all 3 terminals except the grey-white terminal. I know that is the one the relay should active. When not installed I can apply power to it and it clicks but when it's installed there is no power is transferred to that terminal. Also there's no power on the grey-white terminal on the diode. On the diode, which way is it supposed to be pointing? Mine is pointing away from the ground towards the grey-white terminal. This makes sense since there's no power coming from the relay to the diode. BTW I can still jump power to the compressor and get it to power up.

Anyway, I am now completely lost. I need direction please.

 

That diode is only to absorb kick back from clutch coil when is is told to release, That spike can damage your truck . The direction is that it doesn't conduct when power applied . If it did it would blow fuse every time .
Coils when collapsing they apply reverse polarity . So that's when diode conducts and shunts it ,making it semi harmless . That is a large coil with a terrific kick back ,

 

If you can hear/feel the relay clicking, it would seem the AC circuity is working, and the relay is faulty. If you pull the relay, you should have continuity from pin 3 to pin 4, this is the wiper arm inside the relay. This arm will carry the 12V needed from pin 3 to pin 5, when energized.

The clicking sound is the relay energizing, but the wiper arm may not be making contact with Pin 5.

If you remove the relay and short Pin 3 to pin 5, the clutch on compressor should energize. This would prove the left side of the wiring diagram is working, minus the relay.

If the relay isn't energizing, then you need to check the AC high pressure switch and AC clutch pressure switch to ensure they are shorted. If either is open, they will prevent the PCM from sending the ground signal to pin 2 of the relay and the relay will not energize.

 

I think that the only reason you would not get power to the gray-white terminal, while having power to the other three terminals, is the relay is bad. To test this you can remove the relay, jumper terminals 1 and 2 to the battery, and test for continuity between 3 and 5. If there is no continuity, then you know the relay is bad.

 

If you have power on the source side of clutch relay and it wont come thru to grey /wht then you have a terminal problem that the relay plugs into .
Make sure the source voltage is not collapsing when you trigger it , put a test light on source side .
If you can't repair socket on fuse panel then get a junk yard one and replace it .

 

You're not supposed tohave power on the WT-GY until the relay is energized and switches power from pin 3 to pin 5. Same for the wire at the diode.

AND, you're NOT supposed to get power on the PK-YE wire when the relay is installed and is supposed to be on... That's the pin that the PCM has to ground in order to energize the relay. If the relay is out of its socket, the voltage level will be undefined, you cannot test perform a valid voltage test on that wire without the relay installed.

Did you ever follow the directions I gave you a week ago? Doesn't sound like it... which is why you're still floundering about.

Uh, no. You'd have to connect pin 1 to HOT, pin 2 to negative. The relay should energize and then you should have continuity between 3 & 5. You can test these relays with a 9V battery.

 

To clarify the diode polarity the black arrow in diode conducts when its positive in relation to the vertical line symbol . . So in this application the arrow is on the ground side ,the line is on the gray white wire side , so it does not conduct when power is applied.
This relay is controlled by the pcm it supplies the ground to the bottom of the clutch relay coil . The pcm collects the info from the pressure switches and ac controls and decides when to ground the clutch relay to bring on the compressor.

 

My PIDS have now changed after wiggling wires and unplugging and plugging the connectors back in. So now there doesn't seem to be a problem with the pressure cycling switch.

I no longer believe there is a problem with the IC.

1. I did scan the pcm. I have an emissions fault for the evap vent solenoid, abs faults for wheel speed sensor and one I can't remember, and one for the passenger airbag light because it's not telling when the air bag is off, but not sure what would cause the pcm to inhibit compressor operation.
2. I have a AC recharge/Recycle machine like the dealer has. I didn't completely fill the system, I only added until it was about 90-100 psi on the low side.
3.Yes I checked and its working. I think that pid was listed in my post.

 

I have tested my relay and it proves to be good. What do you think i should do now?

 

For certain faults like limp mode the pcm can /does shut off ac. I don't know if your codes are one of them . You need to fix your codes anyway .
You need to see if ground signal is coming out of pcm to trigger clutch relay .

 

​​​​​​Sorry I forgot to answer your question. I didn't jump it at the relay, but I did run power direct to the compressor and it kicks on and works. I also tested my relay and it tested good. But I bought a new relay and put it in just in case (after testing it too).

 

He's right.