"Bulb failed" light illuminating when no bulbs are out, S124

OneCarefulOwner

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The "bulb blown" light keeps coming on in my S124 when I turn on the sidelights, but all 6* bulbs I can see as belonging to that circuit are illuminating. If I use the P< or >P switch positions, the bulb warning light doesn't come on. Any ideas?

* front n/s, front o/s, rear n/s, rear o/s, 2x number plate lights.
 

FazMan

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I had a similar problem, luckly mine was an easy fix, I just took out the bulbs and cleaned up the points of electrical contact.
Worth gently tapping the lights to see if any flicker due to a poor contact.
I found that the warning light would stay on even if the bulb worked after a while. Probably senses an increased resistance caused by poor contact. Also it's possible for the filament to be broken but movement causes it to make contact and then it stays for a while and the heat generated forms a poor joint.
I'd be very surprised if it was anything serious.
 
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OneCarefulOwner

OneCarefulOwner

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That sounds great; I know that resistance from LED bulbs can be different and cause this, but simple corrosion hadn't occured to me - I'll grab a scouring pad and give them a clean :)
 

GP801

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Usually its the tail light bulbs (sometimes brake lights but this triggers warning light when pressing brake). Dont have to be blown. Circuit measures change in resistance and can detect changes before bulb actually blows. Also best replaced in matching pairs.
 

b11ocx

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My experience is that the bulbs are about to blow......
 

Smiley

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check that the tail light bulbs are rated at 10 watt - if someone has put 5 watt bulbs in there it will illuminate the warning light.
 

230K

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What he ^^^^^says

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bolide

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check that the tail light bulbs are rated at 10 watt - if someone has put 5 watt bulbs in there it will illuminate the warning light.

Early cars were 5 Watt, late cars 10 Watt. At least they were on the estates...

Nick Froome
 

Andi968

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A little tip is this weather is once contacts are clean smear a small amount of Vaseline on connecters ensuring not to get any on the glass itself.
 

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