When I switch from heat to cool or cool to heat, the servo on my 1983 XJ6 does NOT move. This is what I have done so far with NO joy:
Tested the servo with the red & purple wires.
The servo moves perfectly both ways. Also,
the flaps open/close fine when applying
power to the servo. I checked it from the
driver’s side to make sure the power went
across the console to the servo.
I checked the fuses on the driver’s and
passenger’s side cheek panel.
With the amp unplugged and the mode
switch on “auto”, I have power on the brown
wire, but moving the temperature switch
on the console, I get no power on any of the
other wires.
I have tried 8 amps. The servo will not
start with any of them. The fuse going to the
amp is good.
I tried another temperature switch with no joy!
I’m beyond my ability at this stage. Any guidance
GREATLY appreciated!
If they’re used amps it is not entirely unreasonable to think that they’re all dead. Until a few months ago I had a slew of dead amplifiers. I finally decided to toss them out
I’m not asserting that your problem must be the amplifier but diagnosing any other fault is a lot easier if the amp is known to be good
Richard,
Your 1983 XJ6 has the Delanair MK II climate control system. What you described sounds very much like the typical failure mode of the A/C amplifier, Jaguar part number C45402. Check the archives for “A/C amplifier” and you will find decades of posts about the A/C amplifier failures and what others have done, or not done, about it. Including many from me. You will most likely need to remove and replace your A/C amplifier with a known good one to verify that yours has failed. New OEM units are unavailable, all used ones should be suspect because the failure rate is so high, a few aftermarket versions were sold over the years, and a relatively new aftermarket source called Jag-Aire is producing them now. Their website is: www.jag-aire.com. I have no affiliation with Jag-Aire other than as a satisfied customer.
Doug, Richard,
A few years ago I was on the hunt for a good OEM A/C amplifier for my former 1987 XJ6 Vanden Plas because the one in it had failed. I knew that the A/C system worked good because I had a good A/C amplifier in my 1984 XJ6 VdP (one of the Australian aftermarket shotgun shell ones) and swapped it back and forth between the two cars. I bought a supposedly “good OEM A/C amplifier from a running car” on eBay but it didn’t work in either of these two cars with known good A/C systems. The eBay seller refunded my payment but also offered to send me another one if I wanted to try it out. He did and that one was also bad. I offered to test any others that he had at no charge, as long as he paid for the shipping. I told him that I would buy at least one, maybe more if they tested good. He sent me a few more and all of them were bad. He was devastated because he thought he was sitting on a gold mine of A/C amplifiers. As a temporary measure I purchased one of the Jag-Aire manual control units and used it until I could source another working OEM or aftermarket unit. I lucked out when my 1987 XJ6 parts car had a slightly different aftermarket shotgun shell unit that worked great.
Based on my experience I believe that all OEM A/C amplifiers should be considered guilty unless proven innocent. Thank goodness our 1990 V12 VdP and 1990 XJ-S convertible have the Delanair MK III with a different design without the trouble prone “brown brick” A/C amplifier.
This is an interesting thread for me as I am neck deep in my 1985 xj6 Delanair 2. I have exchanged emails with Gary at Jag-Aire a few times and am thinking of using his manual control even if my amp and feed back pot test good. Do you prefer the Delanair automated operation with the amp instead of the after market manual control? My thought is if the amp and feed-back pot are know weak links, why not go around them if possible. I have absolutely no problem blipping a rocker switch to fine tune the temp. I never want to take this unit out of the car again!!
Dave,
I was preping both my 1987 XJ6 Vanden Plas and 1984 XJ6 Vanden Plas for sale so I wanted both of their Delanair MK2 climate control systems to operate as originally designed with properly functioning fully automated A/C and heat. I didn’t want to have have to explain to a potential buyer about a “jury rigged” system that was different from how it left the factory and explained in the handbooks. I figured that might result in lower sale prices or no sale.
My 1984 XJ6 Vanden Plas already had an Australian “shotgun shell” amplifier while the 1987 XJ6 Vanden Plas had an OEM unit that worked but then failed. So my interest in the Jag-Aire manual control unit was as a cost effective temporary solution as I preped that car for sale so that I could drive the car with air conditioning until I found a good A/C amplifier (OEM or aftermarket). As it turned out my crash damaged 1987 XJ6 parts car had an inoperative A/C system but a slightly different shotgun shell aftermarke A/C amplifier that worked, so I installed that. So I sold both XJ6s with fully functioning automated A/C and heating climate control systems but neither had an OEM A/C amplifier.
I was pleased with the Jag-Aire manual control unit because I was the only one driving the car at the time and I knew how it operated. I am not sure how it would have been received by the other drivers in our family. If I was going to keep that car I might have just kept the Jag-Aire manual control. I sold the Jag-Aire manual control unit on eBay shortly after selling my last XJ6. Our 1990 V12 VdP and 1990 XJ-S both have the Delanair MK III which fortunatly doesn’t use the “brown brick” OEM A/C amplifier.
Thank you for your opinion Paul, my XJ6 will never be for sale. It is my first Jaguar and my last car build, so it’s being rebuilt the way I want it. My wife’s Escalade has fully automatic climate control and quite frankly I don’t care for the controls on it over my Suburban with manual climate control. The reason for my post was to see if the Jag-Aire manual control functioned without undue fiddling. I have no question of the quality of their products.
**
As others points out, Richard; only a failed amp will present the symptoms and test result you present…
The AC amplifier only controls the servo, the servo then operates all functions - to alter temps the servo must be repositioned. Which requires either a functioning AC amplifier - or manual control of the servo. There is no ‘ifs’ or ‘buts’…
As the servo itself seems fully functional you have the alternatives presented by others - it’s as good as it gets…
