I have read through other threads that were related to my issue, but unable to resolve my A/C problem. I have a 2001 Coupe with the ULEV F23A4 motor, Auto Trans. My A/C stopped working last year, but blower and heat work fine. I didn't have any extra $$ to put into fixing my car so I just drove my truck in the mean time. Now I'm really hating the 12mpg 50mile daily commute and need my car going again. I enlisted the help of a friend who is a Nissan mechanic and off the bat he was able to get the Compressor to fire up using a power probe tool by making contact directly to the connector at the Compressor. The pulley on the side of the compressor spun right up and the A/C lines got ice cold. He prodded and checked for a while longer and determined it would be a good idea to replace the Pressure Switch on top of the Dryer. I took my car to his shop, he evacuated the A/C lines, replaced the switch, then recharged the system to spec. After, still no A/C compressor engaging. When Pressing the A/C button on the panel in the car, the green light comes on, but the compressor doesn't, nor does the Fan on the condensor. We swapped the A/C clutch relay with a working identical relay and it still didn't work.. HOWEVER the clutch did engage when we used a paperclip to jump the relay. Any help with this issue is greatly appreciated. Thanks in advance.

 

Suggest checking for 12V at the compressor when compressor is commanded by AC button w/ blower On.

If you have 12V and no compressor action, the comrpessor clutch gap is too large and must be reduced by removing a shim from beneath the clutch plate.

If you don't have 12V, then AC system is not being energized through the AC relay by ECM supplying ground. Thermostat may be open which prevents ground being supplied to signal ECM through cooling fan controls. You could try jumping the AC thermostat leads (you'll need wiring diagram for your vehicle).

good luck

 

I have the diagram in Haynes manual, but it's not the easiest thing to read that's for sure. Is there a better manual out there... at least cheaper than All Data?

 

Check automanualsource.com for an OEM download manual for $21.99. I think they have your vehicle.

good luck

 

Hey Texas, been a long day.. just got home with a new Innova Equus 3306 Multimeter I pickedup at the auto store. I'm not sure what setting I'm supposed to set this thing to... I'm a total noob with electronic troubleshooting with multimeter.

 

Update: I was trying to test different clips (@ compressor, @ dryer, @ Fans) and wasn't able to get anything. That's with the car running and A/C button engaged, blower on full. I decided to jump the Compressor Clutch at the relay with a paperclip to see if that would change the readings.. that way if the clutch worked and i tested power at the Compressor clip, I'd know it was my lack of electrical experience. Well.. The clutch engaged so i reached back in the driver side for the multi meter dummy sheet .... that's when it happened.. a deafening screech from the compressor. I shut the car off quickly and the sound continted another few seconds before stopping. Smoke was coming out from the engine compartment. I took out the paperclip and put the Relay back in. At this point... I'm wondering if the AC compressor was bad this entire time?? Any thoughts?

 

You may have been experiencing high pressures which would disable the compressor. Forcing it to run may have led to failure.

Alternatively, if you force an empty system to run (LP cut-out disables normally), then no lubricant is circulated and compressor may sieze quickly.

good luck