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Heater fans inop?

rvdz-dummy
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Heater fans inop?

Postby rvdz-dummy » Thu Apr 04, 2013 1:37 pm

Hi again guys!
Having successfully sorted out the rotten fuel lines on my '92 XJ40 3.2 Sovereign, onto the other minor niggles!!
I have no heater fan operation at all - neither fan do anything at any speed setting??!! -- reading through the threads in relation to this common problem, I cant decide the best plan to fix this, as from my way of thinking / reading, the heater fan system has seperate relays & fan motors for left & right, so it seems unlikely for any of these compnents to fail at the same time?? ( I have of course checked all the fuses! ) ........do I deduce from the lack of operation on both sides that the most likely culprit is the fan control switch itself, -- again, cant decide whether switch failure would cause complete failure, or the fans should run on 'full' speed?!

Any help is much appreciated!
Thanks,
Chris.

[59927]

naki_k
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Re: Heater fans inop?

Postby naki_k » Thu Apr 04, 2013 3:05 pm

chris, this has been a much discussed topic recently, so did you read all the recent threads? there must be atleats 5-6 separate recent threads.

but the first thing i check is if there is 12v at the motor plug lead. with the engine on and some temperature so that the fans should be getting some power.
have they ever worked? both on all speeds, or just stopped now?
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
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Breaking 40/ 300

naki_k
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Posts: 27415
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Location: Kirton, nr Boston, Lincolnshire

Re: Heater fans inop?

Postby naki_k » Thu Apr 04, 2013 3:08 pm

88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

naki_k
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Posts: 27415
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: Heater fans inop?

Postby naki_k » Thu Apr 04, 2013 3:10 pm

i think this topic really needs a big post n the how to section? it seems so many heaters are packing up right now
Last edited by naki_k on Thu Apr 04, 2013 5:55 pm, edited 1 time in total.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

MagicDoormouse
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Re: Heater fans inop?

Postby MagicDoormouse » Thu Apr 04, 2013 4:55 pm

A good point well made Naki! It is an intimidating job but once done it becomes SO much easier the next time?
1990 Sovereign (Brian)
1994 Sovereign Silver
1993 Daimler (Parkhouse)
1990 XJR Solent
1993 Daimler Double 6
1993 XJR Flamenco
1991 XJS V12
1976 Capri 3.0 V6

rvdz-dummy
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Re: Heater fans inop?

Postby rvdz-dummy » Thu Apr 04, 2013 9:58 pm

Both of mine packed up as well. I used a How To guide on the internet posted by someone who did theirs on an XJS. The tasks were pretty similar to fix them.

If anyone needs to buy the transistors or diodes for their project, I have some left over that I can offer. Send me a PM

old del boy
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Re: Heater fans inop?

Postby old del boy » Fri Apr 05, 2013 12:47 am

Chris Russ wrote:Hi again guys!
Having successfully sorted out the rotten fuel lines on my '92 XJ40 3.2 Sovereign, onto the other minor niggles!!
I have no heater fan operation at all - neither fan do anything at any speed setting??!! -- reading through the threads in relation to this common problem, I cant decide the best plan to fix this, as from my way of thinking / reading, the heater fan system has seperate relays & fan motors for left & right, so it seems unlikely for any of these compnents to fail at the same time?? ( I have of course checked all the fuses! ) ........do I deduce from the lack of operation on both sides that the most likely culprit is the fan control switch itself, -- again, cant decide whether switch failure would cause complete failure, or the fans should run on 'full' speed?!

Any help is much appreciated!
Thanks,
Chris.


If the switch failed it wouldn't run on any speed , the only time they resort to running only on full speed is when the Darlington transistor is defunct , my bet is the control switch which is common to both blowers but then again you could have trouble with both fuse boxes , time to get stuck in checking connections , power supply etc ,

Derek..
'93 4.0L Daimler, solent blue,
'93 4.0L Daimler, Westminster,
'85 2600 Rover sd1 vdp oporto.

daimler jack
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Re: Heater fans inop?

Postby daimler jack » Wed Apr 10, 2013 2:34 pm

well the ones on the daimler have stoped working one side whins and doesent develop any air the outher is buggerd competaly

jack
1991 Daimler 4.0 auto (long term project)
1986 jaguar 3.6
1991 Daimler 4.0 auto
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MagicDoormouse
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Re: Heater fans inop?

Postby MagicDoormouse » Wed Apr 10, 2013 5:26 pm

stranraergraham wrote:well the ones on the daimler have stoped working one side whins and doesent develop any air the outher is buggerd competaly

jack


You know what to do Jack!!!!!
1990 Sovereign (Brian)
1994 Sovereign Silver
1993 Daimler (Parkhouse)
1990 XJR Solent
1993 Daimler Double 6
1993 XJR Flamenco
1991 XJS V12
1976 Capri 3.0 V6

M-e-l-l-o-w
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Re: Heater fans inop?

Postby M-e-l-l-o-w » Thu Apr 11, 2013 12:19 pm

It is not uncommon for both fuse boxes to fail, especially if there has been moisture getting in to the foot wells.
So before you start replacing things, as others have said it is best to test for 12v at the plug into the blower boxes first.
This should be a constant un-switched 12v feed, but you will need to test it with everything plugged in and the ignition and fan turned on as the fuse box faults can often only show up when the system is under load. So testing for 12v with the blower unplugged may not show up the fault at all.
The wire will be one of thicker ones and it will be brown with a blue stripe or brown with a purple stripe depending on the side of the car.(This wire comes direct from the lower fuse box.)
Only once you know you have 12v at the blower box is it worth looking at anything else.

On the 92 cars there is also a fuse in the centre fuse box (No9 I think?) that powers the a/c logic that is worth checking.

Mellow
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