Flashing rear lights, any suggestions welcome

Hiya,

Failed the MOT at the weekend. One of the failed points was that the rear lights flash when on at the same time as the signal lights. I've checked the ground to the boot floor and it's fine. I've moved the whole thing and still have the problem.

Does anyone have any ideas before I start pulling the wiring to bits? Just as an extra note I've noticed that when the handbrake is on the warning light for that also flashes with the indicators. Does that suggest that the problem might be in the fuse box area?

Any ideas more than welcome.

Cheers

Matt

Definately sounds like a bad earth to me, is it happening on both sides??

Agree bad earth some where.

Have a look at THIS
post for locations.

Sounds like a case of the classic 80 symptom F|ord Disco Lights.
I also believe this is a bad earth or bulb fitting issue. Try cleaning the earths/refitting bulbs and hope that works

Thanks for the replies and all your help.

Each side only flashes when the same side signal light is on but the handbreak light flashes when either is on.

I did think that it might be a bulb issue but after thoroughly cleaning both rear light units and bulbs it's had no affect. Given that both sides have the same symtoms I've been thinking earthing problem as well so will have a look at all earthing points that might relate to the circuits in question. After thinking about it last night I'm inclined to suspect the earthing point by the fuse box as I've had rain water running down the bonnet release cable in the past and dripping onto the fuse box which could have caused some rusting on that particular point.

If that doesn't seem to be the problem and I don't get any success with any of the other earthing points I'd be looking at the fuse box itself. Does that sound about right?

Once all the main earth points have been checked and cleaned(see previous posts) you might need to check the dash as the handbrake light should not do this. I have not heard of that light flashing as well, but from my problems earlier on in the year I cleaned all earths including the bottom of stering rack and suddenly the battery doesnt go flat, the lights are brighter and my horn sounds almost like a horn now.-Possibly check connections of all wires from the rear to the fuse board with a multimeter.

Fuseboard would be my guess …….after checking the earths

This is a trial and error problem, good luck fixing it   .

Thanks everyone!!!

It's going to be Thursday night before I can have another look at it but I'll let you all know how I get on.

Matt

MATTG said

Thanks for the replies and all your help.

Each side only flashes when the same side signal light is on but the handbreak light flashes when either is on.

I did think that it might be a bulb issue but after thoroughly cleaning both rear light units and bulbs it's had no affect. Given that both sides have the same symtoms I've been thinking earthing problem as well so will have a look at all earthing points that might relate to the circuits in question. After thinking about it last night I'm inclined to suspect the earthing point by the fuse box as I've had rain water running down the bonnet release cable in the past and dripping onto the fuse box which could have caused some rusting on that particular point.

If that doesn't seem to be the problem and I don't get any success with any of the other earthing points I'd be looking at the fuse box itself. Does that sound about right?

I have this exact same problem but only on the passenger side! Did you get to the bottom of it? Was it a dodgy earth and if so which one? Could save me loads of time with a multimeter!
Thanks
Richard