Adam,
Correct…there are travel limit switches…if they are good…you should have no problems…obviously if a limit switch fails…you can destroy the servo gear train. But with a momentary switch, the servo only has power when the switch is activated…and in motion.
I recommend a fuse be inserted in your wiring…and should be fuse no higher than 1 amp fast acting fuse.
Cheers
Gary
That will help a ton. Thanks Gary!
It seems like there are quite a few options for replacement AC amplifiers. Are there any amplifiers that are recommended more than others?
Adam,
I am only aware of one currently in production.
The Australian amp from Caulfield Jagaur I think stopped production somewhere around 2011 and a very similar time for the one from Johns Cars in Texas.
That said…used ones occasionally become available. The solid state amps seem to me to be slightly more easily damaged as the internal components are near their maximum rating.
Cheers
Gary
Adam,
If you want to see pictures of the OEM A/C amplifier as well as some of the aftermarket ones search the archives for my post from July 2018 titled something like “Five different kinds of Delanair MK II A/C amplifiers”.
Those pictures show units found in my two Series III XJ6 VdPs, the three XJ6 parts cars I puchased and parted out, as well as units I purchased online.
Most of the OEM units I have had have failed at one point or another, some were bad when I got them. All of the aftermarket ones worked and continue to do so. Be wary of any OEM units you see for sale unless the seller has recently tested it in a running XJ6 WITH A WORKING A/C SYSTEM. I have purchased used units from sellers that advertised that it “came from a running XJ6” only to be disappointed because it did not work when I received it.
Given the choice between an OEM A/C amplifier or an aftermarket one I would recommend getting the aftermarket one. In my opinion there are only two kinds of OEM A/C amplifiers, ones that have failed and ones that will fail. 
Paul
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Don’t know why Gary didn’t mention Jag-Aire, Adam…
Chasing a working AC amp is likely worth while - though the manual control described serves OK, but require driver inputs…
Before preceding; disconnect and reconnect both the servo and amplifier multiplug - possibly using contact cleaner. Then retest servo action with the temp control - the problem may just be bad connections.
And do test out if resetting the servo as you have done have the intended result on cabin heating and cooling - engine warmed up. At max travel the servo gives full heat one way, and max cooling at the other. This may reveal problems that requires further actions - like heater valve action…
Frank
xj6 85 Sov Europe (UK/NZ)
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Thanks Frank,
I try to respect the rules of the forum and not advertise my business… My goal is to help folks understand the Delanair system…and effect any repairs…regardless of where they get their parts.
Cheers,
Gary
I used the door lock switch on my XJS because of it’s convenient location on the center console, and because the door lock solenoids were screwed up anyway.
This is the kit I produce which fits into the ashtray. All plug and play and installs in about 15 minutes and ties into the original harness plug. No cutting…and completely reversible.
It’s working!
A big thank you to @Frank_Andersen and @Gary_Crosby for all of the assistance. After giving Gary a call and talking through the wires on the AC amplifier, I was able to quickly identify that the fused ground from the AC amplifier was disconnected. After buying a new fuse holder and grounding it back to the heater box the heater started working again.
Thanks again forum members for the assistance!
Adam,
Excellent news!
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We can only offer possible lines of investigation, Adam, based on feedback.
While the repair is usually easy, finding the fault is not. Symptoms usually point in many directions, they are seldom conclusive - so all is finally up to the owner.
So the kudos are all yours; well deserved result…
Frank
xj6 85 Sov Europe (UK/NZ)
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