[xj] On to my next problem...climate control!

First I would like to publicly thank Dr. Andrachuk for his
help with my engine noise…valve lash!

My climate control has no airflow on defrost and both times
when I have tried it the heater valve under the bonnet stays
open (no vacuum). Here in Florida…that is a problem! I
bypassed the normal vacuum system for now and have a direct
vacuum source so it closes fine and makes driving much better.

Does anyone have a troubleshooting guide for this system on
an 85 SIII? I have checked the vacuum and all of that
plumbing is correct (except for my temporary modification)
so now I need to dig deeper and make the whole system work.

After that cruise control…and so on…and so on…and so
on…AHH I love this stuff!!!

Thanks in advance,

Woody–
I strongly support the Fairtax…Do you?
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In reply to a message from Woodys84XJ6 sent Tue 28 Apr 2009:

This is a complicated system and I would recommend getting a
manual. The Jaguar one is quite good.

In principal the vacuum is used to control the water valve
and the internal fascia vent. In defrost the water valve
should open and the fascia vent should close pushing all air
to the windshield.

Control of the vacuum and fan motor speed is controlled by a
series of relays and a camshaft driven actuator. This
actuator is driven by a servo motor which again is
controlled by an amplifier that compares the in car temp
with the set point.

When you go from normal to defrost the fan speed should go
to max and you should hear the servo motor moving. If you
hear no movement one possible scenario is the amplifier fuse
which is in the ground lead of the amp. It is tucked away
behind the front part of the transmission tunnel console in
the drivers foot well.

The water temp switch will also inhibit the operation as it
will prevent power going to the motors if the coolant temp
is too low, preventing cold air being blown into the cabin.
This is mounted to a pipe that goes into the heat exchanger
and is up under the dash on the drivers side.

Alex P–
alex paterson
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In reply to a message from alex paterson sent Tue 28 Apr 2009:

Good advice Alex. Just a minor plea - not 100% relevant in this case - to use left and right rather than driver’s or passenger side where relevant, as this is incorrect for UK, Oz, South Africa, New Zealand, Japan etc where climate control parts are concerned.

We are used to ‘translating’ but newbies or archive searchers might be misled. As we know from the current interest in influenza epidemiology, sometimes it is better to try and minimise problems at the source.

Pete
XJ Admin–
68 E-type OTS, 96 X300 XJ12
Cambridge, United Kingdom
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In reply to a message from Woodys84XJ6 sent Tue 28 Apr 2009:

Woody

There’s a trouble shooting guide in the service manual. There’s
also a detailed (60+ page) training book which Jaguar published.
This is available on the supplements CD. Both these can be
obtained from the JDHT via a link on J-L.

From the sound of it you have more than one fault. Selecting
defrost should produce highspeed blowers. If it doesn’t there’s a
fault on the switch or on the relay. If the fan blows at other
settings, my bet is that the switch is faulty. Check for voltage
on the green/slate wire at the relay.

The vac issue needs the routing of the coloured plastic tubes
investigating. You are looking for a red tube coming from the mode
switch running to the firewall connector. Is this in tact and is
vac being supplied to it? This assumes that the servo is rotating,
do flaps and fan speeds change in response to temp knob movements?
There’s a diagram (based on the one in the Jag manual) of what
should happen and when in my photo albums.

There’s quite a good diagram on the SK Jagtech site:
hthttp://tinyurl.com/2z9wku–
The original message included these comments:

My climate control has no airflow on defrost and both times
when I have tried it the heater valve under the bonnet stays
open (no vacuum). Here in Florida…that is a problem! I


al mclean '93 XJS 4.0 - '84 4.2 Daimler - '84 DD6
Telford, United Kingdom
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The archives and FAQ will answer many queries on the XJ series…
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Woodys84XJ6 wrote:

First I would like to publicly thank Dr. Andrachuk for his
help with my engine noise…valve lash!

My climate control has no airflow on defrost and both times
when I have tried it the heater valve under the bonnet stays
open (no vacuum).

Of course it does, Woody - in ‘def’ all vacuum is removed from the
system by intent, defrost is not meant to be cold…:slight_smile:

In this case the fault is in the fan circuitry - and the first question
is if this is the only position without active fans? Ie do the fans runs
as intended in ‘low’ ‘auto’ and ‘hi’…? It’s a must know for
troubleshooting this aspect…:slight_smile:

Another question arising; are you actually driving with the ‘def’ on -
it is usually only used briefly to clear the windscrren under some
conditions. Set to ‘def’; all temp control systems designed to maintain
a comfortable, and constant, cabin is disabled. For a complete
diagnostic the system’s behaviour in ‘auto’ is required in any case…:wink:

Frank
xj6 85 Sov Europe (UK/NZ)> Here in Florida…that is a problem! I

bypassed the normal vacuum system for now and have a direct
vacuum source so it closes fine and makes driving much better.

Does anyone have a troubleshooting guide for this system on
an 85 SIII? I have checked the vacuum and all of that
plumbing is correct (except for my temporary modification)
so now I need to dig deeper and make the whole system work.

After that cruise control…and so on…and so on…and so
on…AHH I love this stuff!!!

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

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In reply to a message from PeterCrespin sent Tue 28 Apr 2009:

Yes a good point Peter didn’t realize so many still on the left.

Alex P
))
Good advice Alex. Just a minor plea - not 100% relevant in
this case - to use left and right rather than driver’s or
passenger side where relevant, as this is incorrect for UK,
Oz, South Africa, New Zealand, Japan etc where climate
control parts are concerned.
))–
alex paterson
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

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