2nd Gen Non-Engine/Transmission A\C....Compressor still won't run!

[klaybus]

OK... Heres my story! AC stopped working this spring. Checked low & high pressure switches by by-passing. No compressor Run. Took to Midas for a service, refrigerant full, relays working, fuse OK... . Power from switch to PCM OK, no power from PCM to compressor. Put 12 volts to compressor & compressor still wouldn't run... . All of this for $77 & still where I started at... . NO A\C!

Took to the dealer today for diagnostics... ... . Another $100 + Tax to try & figure out whats goin on. Any suggestions? Nothing from earlier threads have worked thus far.



Clay

 

[y-knot]

Ok i'll give it a shot. takeing into account, that the fuse is good(fuse at fuse panel), and your pressures are right. There is an air conditioning relay, located in the power distribution center (PDC) in the engine compartment. Remove the relay and check for continuity. Check for battery voltage at the number 30 cavity in the PDC. Threr should be voltage present at all times. cavity 86 should have voltage when key is on.

On the relay 1. terminal 87A to 30 should have continuity

2. terminal 87 to 30 no continuity

3. terminal 85 to 86 75 olms resistance

4. terminal 85 attach grond wire

terminal 86 attach 12v supply

relay should change states (pull in)

continuity between 30 and 87

open between 87A and 30



hope it helps

 

[Gizmo 007]

Assuming you have already tried swapping the A/C relay with another relay, such as the horn relay... Hey, we all overlook the obvious



Try this... Let's completely isolate the compressor.



Unhook the connector at the compressor.

Using a volt meter, put red lead on hot wire (harness connector, not compressor). Put other lead to ground. What volt reading do you get? If voltage is present, the clutch coil is bad and must be replaced.



If no voltage is present we need to check the relay socket in the PDC. Open the Power Distribution Center cover. Locate and remove the A/C relay. On the relay, there should be numbers or a diagram indicating which terminal is which. Locate where the terminal labeled "86" would be. With the key switch turned ON, 12 volts should be present at terminal "86". If no voltage is present check fuses in PDC.



Now find terminal "85". This is the terminal that the PCM controls to activate the A/C clutch. Set your meter to "continuity" (where it beeps when you touch the leads together). Place one lead into terminal "85" and the other to ground. With the A/C switch off, there should be no continuity or "beep". With the A/C turned on, there should now be continuity. If no continuity, check the gray wire at PCM connector C for continuity between terminal "85" and PCM. If there is continuity throughout the gray wire, check the switch sense wire from the cab to the PCM.



Note: THE WIRE FROM THE PCM WILL NOT SHOW VOLTAGE. IT WILL BE GROUNDED. DO NOT APPLY VOLTAGE TO THIS WIRE!



If everything is good so far, now check terminal "30". There should be 12 volts present at all times. If voltage is present, check continuity between terminal "87" and the compressor connector.



If all of the above check out ok, you have isolated the problem to a bad relay. Swap out relays and test for voltage at the compressor again.



If you still can't get voltage to the compressor, PM me. I'll try to help in any way I can!

 

[klaybus]

GIZMO Y-NOT

Guys,

Trucks at DC. I appreciate all the suggestions & ideas you have. I wish my earlier posts had been answered as fast and as complete on the troubleshooting. If DC can't get it or it runs over the $100 & Tax on my troubleshooting quote I'll be picking it up un-repaired & trying all of your suggestions. I'll keep you posted.....



Thanks again!



Clay