I bought the 1996 XJS 6 cyl convertible last fall but did not drive it before putting it away fro the winter. I got it ready for the road this Spring and have had it out several times and it runs great. Today was the first warm day of the Spring for us so my wife and I took it for a ride in the Adirondacks Mtns. I figured that I would try the AC to make sure that it works. It did not at all. When we got home I checked the fuse and that was fine. I saw that the AC clutch was not turning but I thought that might be because the R-134a refrigerant was possibly low. I picked up a AC Pro recharge kit but as soon as I attached it to the low pressure port it read overcharged.
I noticed that the "manual" button on the dash climate controls would not light up when pressed. Does anyone have any thoughts as to if this could be related to the problem.
Any suggestions as to the issue would be appreciated (bearing in mind that I am not at all mechanically capable). Otherwise it will be off to find a service center that can handle this, or just not have AC.

 

Check for power at the relay, I remember it's the third one back on the drivers side (LHD). You have the two headlight relays then the A/C. There is also a fuse for the A/C in the same location I believe. I know with the relay out I didn't get any power to the clutch or the manual button. The high pressure is OK for the system being off, it will balance as soon as you figure out why the compressor is not coming on.

 

Thanks Time-Pilot,
I after reading your post I tried swapping relays with the horn relay but the horn works with the AC relay inserted (on the passenger LHD, side on my car) and the ac still does not work. I have not located another AC fuse aside from the one in the passenger compartment right hand fuse box but I will keep looking.

P.S. I found a AC control fuse in the fuse box on the inside left hand fuse box but that was also good.

 

You can see that fuse is #11 under the hood, it needs to be checked and checked for power. These diagrams will allow you to track power all the way to the manual switch.

 

Thanks again, Time-Pilot. My next step will be checking out the engine compartment forward fuse box for that fuse. My Vehicle Care booklet indicates that there is a 25 amp "air pump" fuse in that box so maybe that is the one for which I should be looking. Looking at the AC system diagram I believe we have the same system but the locations of the fuses in their respective boxes have been changed. In the diagram the right hand engine compartment fuse box fuse is listed as "Fuse 16", in my XJS it is fuse 4. The diagram shows the engine compartment fuse box fuse as "Fuse 7" while my Vehicle Care booklet states that fuse is for the Left-Hand Front Side Light. I will be checking.

Thank you for the assistance, it is appreciated. Even if I am not able the fix the problem I have learned more about the car.

 

STOP!

You cant diagnose AC systems haphazardly. You'll bklow it up and make a mess of everything.

You need a real set of gauges. both low and high sides. What pressure was the low side.? was engine running? sure its the low side?

If its overcharged nothing you do electrically will fix it. it will only blow up the system. so STOP and get some numbers for me

 

Yes, at this point I have stopped. I checked the fuses and relay and they were all good. I tried one of those AC Pro self R-134a refill cans with the simple gauge. I had the engine running and the AC on the coldest setting. I attached the can to the low pressure port (it was the low pressure port) and as soon as I attached it the gauge went into the red to about the 100 psi point. I did momentarily press the trigger release on the can and the pressure reading dropped down to zero. Something did not seem copacetic so I disconnected the hose.
I don't have the proper double gauge set up hose system to do a real diagnosis. I will either do without AC or bring it to a knowledgeable repair shop. If I fool around with it any more I fear I would do more harm than good. Of course I may change my mind tomorrow.
Thanks.