Fog light and rear demister stuck on

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bussell
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Fog light and rear demister stuck on

Post by bussell »

So I have temporarily remedied this by removing fuses, which means no horn.

I turned fog light and demister on recently and now they won’t turn off??

Obviously fog light only comes on with lights but a bit embarrassing in the dark.

Where should I look, did both switches fail simultaneously?

Any advice?
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Re: Fog light and rear demister stuck on

Post by Way2go »

You need to check through the circuits & measure switch activity with a multimeter. Do the switch lights go bright & dim with switch activity? This would tell you if switch is latching but is a secondary contact within so does not confirm main contact action. Removal of F10 wll disable both the Fog Lights and the switch dim/bright
The Rear demist is a separate circuit and also uses a relay so it may not be the switch itself with "welded contacts". As you say removal of the fuse (F8) will disable horn as well as demister but if you remove the relay (R4) instead you will disable just the demister and leave the horn operational, giving you further time to explore.

(Check all earthing points are good as the BX can introduce strange effects when these are not at their best!)
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bussell
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Re: Fog light and rear demister stuck on

Post by bussell »

Thanks very much for the advice, if you push the buttons in the lights go off then spring back and stay on. Guess something has happened but great advice about the relay while I sort it out!
Much appreciated
Ed Beech - Bussell

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bussell
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Re: Fog light and rear demister stuck on

Post by bussell »

Next question, how to remove the switches?
Ed Beech - Bussell

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Re: Fog light and rear demister stuck on

Post by white exec »

Remove the complete instrument pod (two securing wing-nuts at the rear (see Haynes for locations), and unclip the speedo cable behind the instrument) to allow whole pod to come towards you).
Switches can then be released.
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Re: Fog light and rear demister stuck on

Post by RobC »

“Switches can then be released” 😂
Ha you make it sound so easy. 😉 I’m always faffing for bloody ages trying to ease the switches out from the pod.

Advice: take it steady when prising out the switches, and careful you don’t crack the brittle plastic as you get increasingly frustrated!
As well as the wing nuts are there not some screws at the front too, hidden by the plastic panel (which itself is secured with, in my case, tiny torx bolts)
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Re: Fog light and rear demister stuck on

Post by Jaba »

RobC wrote:
Thu Mar 04, 2021 11:41 pm
“Switches can then be released” 😂
Ha you make it sound so easy. 😉 I’m always faffing for bloody ages trying to ease the switches out from the pod.

Advice: take it steady when prising out the switches, and careful you don’t crack the brittle plastic as you get increasingly frustrated!
As well as the wing nuts are there not some screws at the front too, hidden by the plastic panel (which itself is secured with, in my case, tiny torx bolts)
Yes there are 4 to remove at the bottom of the instrument panel. Best to get replacement switch first so that you can see the latches and know where to press - it is fiddly as others say. Have you tried pulling back out the demister switch button as sometimes they get lazy and stiff and do not spring back far enough and then odd things can happen circuit wise. Its sort of next to impossible for two switches to coincidentally fail at the same time
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Re: Fog light and rear demister stuck on

Post by rutter123 »

You will need the fingers of a wizard, a lot of patience and a swear jar.
From memory I think you will need to remove the plastic shrouds from the steering column before you can get to the 2 tiny screws that hold the bottom of the binnacle
Also if any of your bulbs in the dash clocks are blown its a good time to replace them
If it is your switches I've prob got some good used ones
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Re: Fog light and rear demister stuck on

Post by white exec »

Yes, I forgot to mention the front lower edge screws, because they're the easy ones.
The lower lip (with two small torx screws) can be removed without taking the column shroud off.
With the lower lip off, you can see the two larger lower edge screws.

Removing the steering wheel helps with instrument pod access. Mark the spline position/shaft so the wheel goes back in the same position.
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Re: Fog light and rear demister stuck on

Post by bussell »

Thanks all so much for the advice- I agree totally random for 2 to fail simultaneously- however if I push and hold them in they go off!

Really helpful with advice on how to! Now to find some immaculate switches
Ed Beech - Bussell

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Re: Fog light and rear demister stuck on

Post by white exec »

Surprising that both of these switches would fail, especially as they (normally) get relatively sparse use, as switches go.
You might be lucky, and be able top open the switches up, to find out what's going on inside.
However, beware a certain CitroJim's caution: 'These items may contain ping-f*uckits...'.
Chris