I have a 95 XJS 2 + 2 4.0 convertible.. when I turn the AC on the compressor comes on the Low Pressure side gets cold the High Pressure stays warm it trying to work, however, in the car when I press the AC on button the little green light will not come on and Im not getting any air from the front 2 center vents, they are closed and will not open to let the air thru. the vent on the left side of the car will pass air but it's not cold also with the far right side vent same thing. I don't know if a relay is controlling this or if it is a fuse somewhere that is blown. Thanks for anyones help...

 

The center vent is opened by vacuum. There is a vacuum solenoid that receives an electrical signal from the climate control ECU to open and that allows vacuum to the vent. It's a black supply line. Note that there are restrictors to prevent hunting, so it can take up to 30 seconds for the vent to fully open.

Possibilities could be a bad actuator, dislodged vacuum line, or bad solenoid. The solenoids are under the climate control unit, you might see them if you remove the radio, or the side panels on the transmission tunnel that have the vents in them.

If you're not getting cold air I'd suspect either low freon charge or a condenser that is full of bugs, dirt etc and isn't shedding the heat. Try wetting down the condensor with spray from a garden hose and see if that makes much difference. The check valves in the fill ports are known to leak, they are standard GM parts that screw into the aluminium lines. You'll probably need to take it to an AC specialist for changing the ports and a recharge.

 

thanks for the reply..the air conditioning compresser comes on and it tries to cool because the Low Pressure line gets cold, it just isn't blowing cold air in the cabin because the vents are not opening. Im guessing its the Control Module thats bad, could be wrong...

 

The ECU rarely goes wrong, so I wouldn't start there. However, there are 2 blend doors, a top and bottom that have motor driven servos and those can go bad. If you're sure the AC charge is correct, the next thing you can do is rig up a vacuum line to the heater valve on the firewall and see if the air gets colder.

Default position for the valve is open, it takes vacuum to close. So close it off to make sure there is no heat going to the car and see if the air cools. If yes, it could be a faulty heater valve, a vacuum fault, or the blend doors are not being moved to block off the heater.

Have a look at this thread to see the diagrams of the positions of the flaps that are moved by the motors.
https://www.jaguarforums.com/forum/x...ontrol-178835/

 

They are sure proud of those servo motors..Is there any Fuses or relays connected the AC system..I can't find any fuses...thanks for your help...

 

Fuse #8(10A) and fuse #13 (5A) on the left fuse panel. 2 relays are inside each blower case for high speed.

 

Well 8 and 13 are good...are there any fuses for the Servos or anyway to test them..? Thanks.

 

No fuses for the servos. Best way to test is to pull them, but leave them connected and have the system on and go from hot to cold and see if the motor moves.

Lower one isn't too bad to get to, although the ECU needs to be removed. Be gentle with it, it's very expensive to replace and is unique to the XJS. Upper servo is a pain, steering wheel comes off, both airbags come out and the dash comes out to get to it.

 

Hollycow !!! thats not good.

 

All that trouble just to get the little green power light to come on, thats unbelievable.

 

If I have to take the steering wheel and airbags out I will just go without AC..not worth the money or effort.

 

When you have the system on and put it in defrost does the air go to the defrost vents and full heat? If you put it on fan speed 3 and temp to 65 and manual button selected does the air come out of the dash vents ( except the centre one, as you said that doesn't work). Is it coolish? Does the clutch on the AC compressor engage?

Then switch it to 85, does the air get hot? Does most go to the floor? The airflow to the dash should be noticeably less now.

Remembering it can take up to 30 seconds for the system to respond and everything to settle down.

 

Like I said the Compressor Clutch engages and it's trying to work, the Low pressure line gets Frosty and the High Pressure Line gets warm, so I know its trying to work, but something seems to be restricting it from the cabin and going thru the vents and the center vents do not open and the Little Power Green Light on the Control Module does not come on. The heat side always works.

 

My guess is it's in the vacuum system somewhere. Check that the system is actually getting vacuum at the supply ( sorry I only know where that is on the engine on a V12, not the 6) and look for any dislodged vacuum lines or split rubber fittings. Remove the side trim panels an/or the radio and you have pretty good access.

 

Yeah..I can remove the radio pretty easily. Thanks for all your help, I will be getting a Factory Service Repair Manual in a few days,,hopefully it will help.

 

I got the AC to work..didn't have to do anything..I just disconnected the Control Module and reconnected it and now the AC is working great...

 

Glad you got it working!

 

Thanks again for your help !!!

 

The lights for the A/C buttons are all red, not green...
But anyway, glad you got it fixed! I wish my problem was so simple.

I'm having a somewhat similar issue. I charged my a/c one day, just a little until it was blowing cold, but not fully charged. A week later it was not cold so I used a big can and did a full charge and it was ice cold. Next morning it was blowing hot. I assumed a big leak. I used a pin and rag to slowly let out the remaining gas, which didn't seem to be much. A week later I bought another can and wanted to add just enough to have cold air without stressing the system enough to leak. Not seeing the bigger picture, I did the recharge procedure again and the gauge was still reading almost-but-not-quite-full when something on the bottom rear of the engine bay blew out, refrigerant oil on the manifold, lots of smoke. I shut it off while it was slowly all leaking out. Since then the only test I've done is bleeding out more gas from the low side port as before, and there is still plenty of gas in there so I stopped short of letting it all out.
What I did wrong: not realizing the high side line still had full pressure and refrigerant when I did the second full recharge, even though the gauge was reading properly during the recharge, but it's possible I was not paying close enough attention and was putting in way too much.
But now I know. Sadly, too late to not have broken something that I now need to locate and repair/replace.
Any input, ideas, advice, and severe scolding are all accepted at this point.
:-/

 

Have you got a vacuum pump and gauges...? If you do you could evacuque it and see if it holds vacuum...If it will hold vacuum for about an hour , you should be good to go...