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sTrying to
Trying to start the process of finding my problem. The compressor does not try to cycle at all. It does not come on jumping the low pressure switch side with the dash selector on or off. Getting underneath I found broken corroded wires in the loom that go to the plug in the picture. This ties back into a split loom going along the valve cover rail and back into the dash area. I can't tell if the plug in the picture is attached to part of the compressor or something in the block.
I am hopeful that it ties back to the selector **** in the dash to signal the compressor. Any information is greatly appreciated. Not sure the compressor could be located in a worse place on these.
So after digging on Rockauto. I've got the same A/C compressor as you do.
Here is some pics of it. Their is a separate electrical plug in literally right next to it. Have to research what the plug actually is but at first it looks like it
has to do with the compressor.
Edit- after looking that sensor on the block is not a knock sensor.
Might be a timing sensor, still looking.
Originally Posted by Evan_P
That’s the crankshaft position sensor connector that your circled.
This is a PCM-controlled A/C clutch ciruit. If the PCM ain't happy with all operating conditions, it won't activate the clutch relay to engage the compressor. The series circuit of the cycling and high pressure containment switches serve as an input to the PCM. The PCM, unless operating parameters preclude it, issues a command to energize the A/C clutch relay which, when energized, switches power from CJB F10 to the clutch coil.
The clutch relay is located in Auxiliary Relay Box #4 located under the hinge for the hood on the driver's side, fenderwell, lower box. Pull the cover off and check to see whether the relay clicks or not (engine running) when the A/C Mode switch is alternated between VENT and A/C. If so, the PCM is happy and is issuing the signal to activate the clutch.
If it does:
Check CJB F10 make sure it is passing power (ALWAYS HOT). It should feed pin 30 (next step).
Pull the clutch relay and jumper socket pin 30 to 87 and see if the clutch energizes. If not, there's an open circuit somewhere between the pin 87 and the clutch oil connector (GY-WH wire).
I was able to get someone to come over and run the selector switch in the cab. Neither one of us heard the relay under the hood click at all. I am not sure which one of the two under the cover were the correct one, but there was no sound. F10 in the cab is good and has continuity on the meter.
Can you further walk me through testing it feeding pin 30 and jumping 30 to 87? Can I use a paper clip or just use some jumper wires I have to test the clutch?
Have you scanned the PCM for any faults? It will disable the compressor clutch if certain faults are present.
Do you have a scan tool or equivalent that can read PIDs in the PCM and auxiliary systems?
Is this a manual or automatic climate control system?
Be sure to read the HVAC FAQs, link is in my signature.
Can you further walk me through testing it feeding pin 30 and jumping 30 to 87? Can I use a paper clip or just use some jumper wires I have to test the clutch?
Any jumper, including a paper clip, should work. The A/C clutch is the larger of the three relays in Auxiliary Relay Box #4. The other two are for the trailer tow stop/turn signals.
Go ahead and jumper those terminals and see if the clutch engages or not. Make sure you're in the correct relay box, not the upper one. It should have THREE relays in it.
Is your OBDII interface and its software capable of reading PCM PIDs?
If I did this correctly I did not get the clutch to engage. I am not sure on the scan tool if it can read PIDs . It is called Blue driver and I use my phone to run it. I will try to find the answer to that question
Thank you for your help.
Do you have battery voltage on pin 30? If so and you jumpered it to pin 87 and the clutch did not engage, then either the circuit is open or the clutch gap is excessive.
Measure resistance from pin 87 to ground, should be a few (3-5) ohms. If open, then that confirms the open circuit.
Here's the road map (schematic) for that circuit. You may have to dig into that damaged wire loom.
Sorry. I set the meter to ohms to run the 87 to ground test. I wasn't able to get a good ground on the body with the test light for the voltage light test on 30 so I ran it to the negative battery post. I just used that ground to also ground the negative on the meter and put the positive probe to the 87 pin on the female socket. It appears i didn't run this correctly.
Thank you
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