All, I have 2002 X-Type with a 2.5 that has auto climate controls.

I am looking for the wiring diagram for the AC. I have checked the fuse under the hood and the relay has power in two locations and you can here a click when you turn on the AC at the relay. I have around 60-65 psi of Freon in the system. I have no power at the AC compressor or power at the pressure switch under the pass wheel well. When you turn on the AC the second cooling fan kicks on also.

 

henry: Wiring diagrams are in this post: https://www.jaguarforums.com/forum/x...6/#post1334545

Figures 06.1 and 06.2 are for Climate Control.

 

DW I pulled the fuse / relay box out to probe the backside. I first pulled the relay and I have 12v at the RU wire (#3 on the relay) with the key on and the AC switch on, I plug in the relay and I get power at the GU wire (#1) and no power to the AC compressor, but I am not hearing the relay click on like before(?). I checked continuity of the RG wire (#5) and disconnected the AC connector and its good. I plugged the AC back in, pulled the relay and jumped a hot wire from the positive battery terminal (and just about burned my finger...which led me to search for hot positive cable and found that it seems pretty common that the battery cable has high resistance...my next project) to the #5 position and the clutch will still not engage. I probed the connector at the AC compressor and the test light showed power on both wires. I am not very familiar with how to read this JAG wiring schematic, where does the BG (#2) go? It seems like a ground problem? Where does the B wire go that goes to ground G17AS. I know that I am making this more complicated then it needs to be.

I disconnected the AC compressor connection and jumped the AC side with a 12v jump box to confirm the clutch is working. I ran the car and filled the system with freon.

 

henry: I'll look at the wiring diagram tonight when I have more time. A few quick answers to your questions:

+ The BG wire from contact #2 on the AC clutch relay goes to connector EN16-034 on the ECM. It's normally an open circuit, and the ECM switches it closed to ground to energize the AC clutch. So the AC relay will click to the closed position and energize the AC clutch only when the AC control panel is on, the engine is running, and Freon pressure is within range (not too high, not too low). On many cars (probably our X-Types, but I don't know for certain), the ECM switches off the AC when the engine is under high load.

+ G17AS is the ground point for the AC compressor. See page 20 of the wiring diagram (page 22 in the pdf) for the locations of all ground points

+ You say "I probed the connector at the AC compressor and the test light showed power on both wires." Are you saying there's 12V's on both wires to the AC clutch? If 'yes', check the black wire from the clutch to the G17 ground point on the generator / alternator bracket. That wire should be grounded, i.e., 0 volts. If not properly grounded, as indicated by 12V on both AC clutch wires, that would explain why the AC clutch is not engaging as it should.

 

Using Page 3.2 for the AC Compressor wiring

The Red/Blue wire at Pin 3 on R6 relay is a permanent 12v battery supply. The Green/Blue one on pin 1 is an ignition switched 12v supply. The Black/Green wire goes to the Engine Control Module that switches it to ground to allow the relay to 'make' and operate the AC clutch through the Red/Green wire supply and the Black ground wire.

You said you had 12v on the both the wires at the compressor, but you would only get 12 v on the Black wire if it was not connected to ground. It should be grounded on the alternator bracket.

 

DW and Astromorg,

Thank you for the follow up, I disconnected the plug at the AC compressor and have 12v on the RG wire and no continuity when checking the B wire to ground. I plugged the connecter back in and made a jumper from the B wire to ground and the AC clutch kicked on.

Thank you for your help.