hello my name is bernard button and my ride is a 1986 xjs v12 in mint condition except when i bought it the heat and air didnt work. the garage put in a new servo and now the heat works. the freon is not leaking and the compesor is running but only heat comes out.

also i put in after draining feron 3 oz oil and 30 oz freon. is that enough? i can see the freon moving threw the site glass

i have 30 oz of freon in and 3 oz of oil not leaking and can see freon moving in site glass and compessor is running and only heat is coming out. i didnt check a/c untill now and i drained system and filled how i told you. what could be wrong with ac?

 

Bernard,

I've copied this from your Intro. Grant has already given some advice on the AC.

Other members in the US and Europe (where we are allowed to work on AC ourselves) will also be able to help.

Graham

 

As for freon charge and the *refrigeration* aspect of the system the best way to determine correct charge is using pressure gauges, as I beleive Grant mentioned earlier. This is work for an experienced A/C technician.

However.....

The refrigeration part of the system might be OK and, instead, you have a problem with the *control* side of the system.

First, when you slowly turn the temp control knob do you hear a faint humming from the dashboard? You should. That would be the servo motor operating. The servo motor changes the positions of the various flaps and valves to control temperature and air flow. If you don't hear a faint humming then the control side isn't working at all.

Next, and assuming you DO hear a humming sound, when you select maximum cooling does air start coming out of the center dashboard vent? It should. This would tell us that the system understands to request for max cooling and is trying to comply.

Cheers
DD

 

Also check the water valve. It allows hot coolant to circulate as a default condition. Vacuum must be applied to the valve bellows to stop the hot coolant from heating the interior. I admit I don't have a V 12 and am assuming that all the Jag systems use a vacuum operated water valve. I wish my 1996 did not use vacuum and computer module operated systems and instead used the tried and true Bowden cables.
RagJag

 

hello and thanks for your replies but on my 1986 xjs v12 what is the heater tap

 

sorry i didnt mention this in my last post but on my 1986 xjs after filling freon the metal pats of a/c hoses they all got frost covered and still now cold air will this help to tell me what is wrong i dont hear the servo or controls make any noise change or humming when truning a/c on

 

The most difficult thing about the XJS is keeping the heater/AC unit functioning properly. I don't even know if the later facelift cars can actually be fixed. I have about given up on the Delanair 111 in my 1996. I have considered removing the entire dash to get the unit out but I don't know if it would be possible to actually get parts to repair it. I have also considered putting manual controls on the doors and water valve. Doing that may not be feasible and may just make a mess of the dash. Do any of you folks that have and have had an XJS know if this can be done.
Thanks for any advice, RagJag

 

Heater tap = heater valve. As mentioned it is vacuum controlled. It is on the firewall, almost dead center....a bit hard to see.

With the engine running have a helper slowly turn the control knob from hot to cold. You should see the little lever arm of the heater valve move.



Cheers
DD

 

There is an 'amplifier' just forward of the radio. The amplifier controls the servo motor. Remove the LH console cheek panel to find it. The 'cheek panle' is the forward section of the console that has the little metal air outlet. Remove the two screws and the outlet and wriggle the pnale forward to remove.

Beneath all the hoses and wires is the amplifier...about the size of a pack of cigarettes...about a dozen wires on a circular connector. Now look for the black ground wire with an inline fuse holder. Check the fuse and report back.

My gut feeling is that you need an new amplifier ...about $200-$300...but there are more checks to be made. Do you have, and are you familiar with, a test light or test meter?

There are three other fuses for the system. Have you checked them?

Cheers
DD

 

The OP's 1986 car should have the Delanair Mk II system. Your Mk III system is a different kettle of fish. I suggest starting a different thread. Mixing commentary on the two different systems in the same thread will get confusing.

Cheers
DD

 

Doug, I was speaking to the difficulty of repairing any computer/vacuum controlled Delanair system, including the 1986. These units are, in my opinion as bad as the Lucas electronic parts installed on Jaguars for so many years. It is a shame that an automobile so beautiful and pleasant to drive had to be saddled with so much electronic junk which seems to be of very low quality.
As for starting a new thread on the MK 3, I did that last year and got no helpful information.
Sorry if I stepped on Zipper 1462s post.
Cheers, RagJag

 

Diagnosis and repairs can be difficult, yes. I've pulled my hair out on a couple.

On the bright side there are a few common/easy fixes that we've learned over the years that often apply.



I agree to a point but *any* of the older 'climate control' systems are tricky no matter the brand. I'm hard pressed to think of even one that has a reputation for beig dead reliable and easy to repair .

Personally I'm happy with manual control systems. Luxury and convenience is fine but I can muster the strength to manually adjust a couple knobs from time to time to attain the comfort level I desire.....and wouldn't feel like a low-life having to do so




Why not try again?



AFAIC no apology needed. The motivation behind my suggestion was entirely practical and not personal. I hope you didn't take it as me jumping on you.

Cheers
DD

 

thanks again u didnt step on me at all you are just trying to help which most people wont bother to do now adays i apperciate your time and only wish the rest of the world was as kind and helpful even if non of your suggestions work

 

Doug, no problem at all. I wish I could find out if anyone has ever taken a Delanair out of an XJS, fixed it and returned it to the hole it came out of. Not easy to do, I am sure.
RagJag

 

hello doug on my 1986 xjs v12 jag u told me were the fuse was near the amplifier and u told me were the other 3 fuses were for the a/c but i some how erased your message could u or someone tell me again where the 3 other fuses are located

 

Each of the two under-dash fuse box has a climate control fuse. The label on the fuse box covers will indicate which ones exactly.

Then there's the amplifier fuse behind the LH console cheek panel

Then there's another inline fuse behind the RH console cheek panel, clipped to the side of the main climate control casing

Cheers
DD

 

hello and thanks again i have located all the fuses but i am alittle cofused is the left hand control panel and right as you sit in car or facing car i know im a bit stupid but thanks for all the help

 

hello its me bernie again or zipper which ever , my 1986 xjs jaguar Doug u have helped me a lot with your answers but now i believe you are right it needs a amplifier but so the gargae doesn't screw me is the amplifier the same as the servo because when i had the heater fixed they said that they put in new servo and that both the heat and air worked but only the heat did and i was understanding the servo controlled the heat and air so are they the same

 

Not stupid. This comes up all the time.

Left and right is (or should be) always expressed from the perspective of sitting in the car and facing forward

Cheers
DD

 

The servo a mechanical device: electric motor, gears, and cams that rotate to physically operate linkages and switches.

The amplifier is the electronic module that tells the servo what to do.

Problem is, 'servo' is often used loosely. Your car has some vacuum-operated actuators that many would call 'servos'.

Cheers
DD