Temp control

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happycat
Posts: 58
Joined: Tue Jul 02, 2013 9:52 am
Location: West Molesey,Surrey

Temp control

Postby happycat » Thu Sep 04, 2014 1:29 pm

Hi I know there's plenty of info about the a/c but I find it very confusing! Any way the problem I have is I can't get any heat to the footwells,if I put it on demist there's plenty of heat rushing up to windscreen but when on any other speed manual or auto I only get cold air on my feet! The fans seem to adjust to each speed setting but do not settle down to slow speed in auto,when I adjust from demist I do get heat blowing in footwells momentarily .is there a simple check I can do ?
1992 XJS convertible 4.0 signal red
2012 XJL Portfolio

almcl
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Location: Shropshire
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Re: Temp control

Postby almcl » Thu Sep 04, 2014 7:11 pm

Don't think 'simple' and the Delanaire Mk III fit in the same sentence, do they?

If you have access to a vacuum gauge, check how long the system holds vac after shut down. If it decays in a minute or two, chances are one or other of the little coloured pipes has come adrift. By no means certain, but it could be the source of the problem. So too could a stuck actuator (there are two which control direction and amount of heat) and a faulty feedback pot.

Others will chime in more possibilities.
Al McL
'93 XJS 4.0 - '05 X type Est 2.0D - '13 XF 2.2D Sportbrake

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CliveRothwell
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Re: Temp control

Postby CliveRothwell » Thu Sep 04, 2014 8:37 pm

Sticking flaps is a good cause. Remove the instrument binnacle and knee panel expose the R/H side of the Delanaire unit and, with the controls set for low speed heat, gently and carefully tap the end of the actuator flap or motor ( I forget which) and, if you are lucky, the unit should kick into motion and move the flaps to change the air flow. I spent ages on exactly this problem with our 4.0 1991 facelift car, consulted Clive at Nene Jaguar, Peterborough, followed his instructions above - and it worked. However, mine has stuck again in the screen position like your car appears to have done and I think it is better to have a clear screen as a result rather than warm feet and a misty screen. Your call! Good luck. I think I did put a comment about my experience on this page a couple of years ago.....

oldtimer
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Re: Temp control

Postby oldtimer » Thu Sep 04, 2014 10:07 pm

Remind me when the change was made from Vacuum operated blend flaps to electric motors

almcl
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Re: Temp control

Postby almcl » Thu Sep 04, 2014 10:51 pm

The change to electric (from Mk II to MK III) was in 1987 but the Mk III retains vac flaps for some functions (blend, screen flaps and so on).
Al McL
'93 XJS 4.0 - '05 X type Est 2.0D - '13 XF 2.2D Sportbrake

happycat
Posts: 58
Joined: Tue Jul 02, 2013 9:52 am
Location: West Molesey,Surrey

Re: Temp control

Postby happycat » Sun Sep 14, 2014 8:12 pm

Sticking flaps is a good cause. Remove the instrument binnacle and knee panel expose the R/H side of the Delanaire unit and, with the controls set for low speed heat, gently and carefully tap the end of the actuator flap or motor ( I forget which) and, if you are lucky, the unit should kick into motion and move the flaps to change the air flow. I spent ages on exactly this problem with our 4.0 1991 facelift car, consulted Clive at Nene Jaguar, Peterborough, followed his instructions above - and it worked. However, mine has stuck again in the screen position like your car appears to have done and I think it is better to have a clear screen as a result rather than warm feet and a misty screen. Your call! Good luck. I think I did put a comment about my experience on this page a couple of years ago.....

We'll I've pulled connectors apart banged and tapped the side of unit and hey presto I have heat :D but now the radio has stopped working :( I give up
1992 XJS convertible 4.0 signal red
2012 XJL Portfolio

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ng4xjs
Posts: 296
Joined: Thu Jul 29, 2010 12:49 pm

Re: Temp control

Postby ng4xjs » Mon Sep 15, 2014 10:41 am

Don't give up, it's an XJS, These minor annoyances do happen from time to time.

Happy days
n


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