Hello everyone!
I've scrounged the forums for anything regarding the problem I'm having with my jaguar but I haven't come across what I'm having an issue with.
I have a 1981 Jaguar XJ6 4.2 that I've owned for several years now. I believe it has a Delenair II HVAC system. The car is an early series 3 so I have noticed it shares many Series 2 pieces and parts.

While owning the car, I have done quite a few things to it but the problem I'm facing now is the HVAC is having an odd issue.
It is getting cold now and I have been calling for heat in the morning on my commute to the office. The problem I'm running into though is, no heat comes out the bottom vents!
Everything else seems to be working fine. When I turn the heat up, heat will blow out of the top vents until the the temperature is satisfied so I know the hot water valve is working. But no matter what I adjust on the settings, it seems that cold air is coming in through the bottom and rear air vents. Thus my feet get really cold and my face gets hot!
Also, the defrost works as it should.

I had my amplifier fail recently but luckily there was a jaguar at my local junk yard (sad to see) that had a shotgun shell type amplifier which fixed my amplifier issues.

During the summer, I did rebuild the a/c compressor and re-charge the system as well as added a switch for turning the compressor on and off manually so I was monkeying around in the wiring and it is possible I unplugged something by accident.

So my question is, is there an electrical connector or a vacuum line that operates that bottom air vents that I may have accidentally disconnected, or is the flap that adjusts the bi-level air passages directly operated from the servo?

Apologies if this is discussed in another post already, but I looked and didn't find anything this specific! Any and all help would be much appreciated!
I'm hoping it is something easy like a wire unplugged, but I'm just not exactly sure where to start.

Thanks,
Ian

 

I don't think it is an electrical issue, must be a Vacuum issue.
Remove the floor vent and panel in the passenger side.
Run the engine until warm, keep it running in PARK
go to the passenger side to watch the Servo Rods open and close Flaps as you:
Set Mode to AUTO
Set temp to 85

Look at the rods to make sure no rods are loose.
Check for any loose vacuum tubes or hoses.

Is hot air coming out of the Center Vent ?
It should not, the center vent should close when in Heat mode, it only opens during air conditioning mode.

 

^
If a previous owner has completed the [worthwhile] “Gardner Modification” that would not be the case:

 

Thanks for the quick reply! I will check on the rods and hoses tonight when I have some time and report back.
As for the center vent, no it remains closed with no air flow from it. I noticed it has stopped opening all together but I know that the center vent only opens when max cooling is called for or something like that, so I wasn't too worried about it not opening, although maybe that problem could be related.

 

Thank you for pointing this out. I did in fact add a switch to my setup to allow for manual fresh air. I will double check that I did that correctly and make sure that this is not the issue as well. I could see where if I installed my switch incorrectly, I may have caused the problem myself but had overlooked that as a possibility.

 

yes, when we start messing with certain systems, unpredictable results always happen.
I thought your system was un-modified.

I am of the opinion that there is no such thing as "fresh air", in any case it is dirty air, full of exhaust fumes, dust, and insects !! haha !

My system is intact, no mods.

 

Apologies, I failed to mention I had done the gardener mod but obviously I must have done it incorrectly and shot myself in my foot.
Last night I went home and uninstalled that "fresh air" switch and put things back to how they are, then ran the car and it seemed like everything was working properly.

When thinking about it, if I really want fresh air, I can use the pull levers that pull in air from around the headlight anyways so there really is no need for that modification.
Thank you all for your help, I'm glad it was an easy fix after all.

 

so your car has the kick panel vents ? I always wanted those but my ''84 came without them.
Glad you fixed the problem.

 

It does, I assumed all xj6 models had those vents, that is the only way heat gets to your feet though isn't it, unless other models had different plumbing?

 

I mean the pull cable vents that lets air come in through the headlights.

 

Ah, yes those are intact in my car. Although I had to fix them as the linkages were not operable when I bought the car. They do come in handy on nice days when there is no need for HVAC. Although I do forget to close them pretty often.

 

Jaguar made the provision for those vents in the 1950's in all models, My 1965 S type has the openings but no cables, I used the round holes for 8" speakers.