Tail light and stoplight gremlin

[Paul Kelley]

Hi

First the offside brake light went, tail lights working fine. Bulb looked Ok but I changed it anyway. Then I switched the bulb holders and hey presto the offside brake light worked - but so did the nearside!. Then I put the tail lights on - they worked too. Result! But then I put the brake lights on with the tail lights and the tail lights went out. Brakes off and tail lights back on. Then no tail lights at all. And now the brake lights work on their own, but don't with the lights on (still no tail lights). Suspecting connection issues I have tried coating connections with Contralube 770 but to no effect. Before I risk wasting money on new but poor quality bulb holders (been there with the indicators) can I ask the Forum's electrical gurus for any ideas?

With many thanks

Paul K

[Bob Heritage]

Bad earth, Old Fords suffer with the same problem.

[alistair260661]

I'd check all yoru earth connections before doing anything else - both between bulb holders and "frame" and also between "frame" to the body of car.

By frame I mean the unit into which individual bulb holders are fitted.

A good starting point is to take all the holders out of the frame - fix up earth cables direct to the battery and test. if that works then put the holders back into the frame , rig up direct earth connections from frame to battery and test. I suspect you may have bad earthing between bulb holders and left and right frames..

You need to do all the bulbs together, often a clear indication of bad earthing is when bulbs work individually (i.e. sides or stop lights on there own), but all together you get weirdness, because the return current (earth) goes down a path it isn't actually meant to - hence some bulbs working and others not........

hope this is understandable and helps.

[Stagsongas]

Bad earth, Old Fords suffer with the same problem.

Someone else who had an XR3i

[Richard G]

Or a Mk2 Escort (Van)

Someone else who had an XR3i

[Paul Kelley]

Thanks guys for your ideas, Alistair in particular. I have done some Youtube trawling under 'car earthing problems' and there are some good visuals for anyone else with this kind of problem. Mostly Americans called Bob (Baaaaarb) but they're good at explaining things!

I had a dodgy Ford once too - a 105e Anglia that would only go straight on or turn left until the steering box had warmed up! It made parking and the first few hundred yards interesting!

Paul K