earthing problem on my brake lights

[hangman72]

hello. can anybody help me? i'm at my wits end because my centre brake light is is working but the two side brakelights are not. i checked the bulbs and the fuses and they're fine. i've know noticed that when i put the car into reverse , my foglight is lit up on my dashboard. i drive a 2003 renault laguna. mileage is 42,000 miles it's a 1.6 litre engine.

please help.

 

[nickso]

have you found the earth then? thats probably the cause. pull all the boot carpets out and look for it/them.

another reason not to buy throwaway french scrap i'm afraid.

 

[hangman72]

thanks for the reply. i didn't find anything in the boot but under the rear seat there is a black wire running from the centre of the floor over to the trim on the rear drivers side door. i had an earthing problem with the indicaters last year which i was able to fix by running a piece of wire from the bulb holder to the body. just wondering if the brakelights problem can be fixed the same way?

 

[wotan]

If you have established that it's definately the earth return thats at fault, then a seperate wire from the lamps to a good clean earth point on the car should work.

Wotan

 

[hangman72]

thanks very much. i'll give it a bash and let you know. thanks again.

 

[hangman72]

i've tried the old "wire attached to the body of the car and touched the other end of the wire to the lamps trick" but unfortunately that doesn't work. however i have noticed that when the fog light or reverse light is turned on, all the lights in the fitting light up very dull. any ideas?

 

[wotan]

Take all the bulbs out of each rear lamp clusters, its possible you have poor connections, or water in the electrics, or incorrectly fitted bulbs, a single filament lamp where it should be a double.

Wotan

 

[Mickymoody]

Laguna electrics shrug! Renowned for electrical faults. rewire what you can.

 

[hangman72]

thanks for all the suggestions. i've tried everthing you said but nothing has changed. my problem still persists. anybody got any more ideas apart from a gallon of petrol and a lighter.

 

[Mickymoody]

You have wired new earths to the brakelights, but still no joy? Is the middle brakelight origional? You might want to disconnect that, as it could be adding to the complications. And then the cause of the light on the dash coming on..

So brake light switch is good, maybe take a feed off that middle brakelight to the outer brakelights (ie reverse what would normally be) ?

Possible fusebox problem? Take out relevent fuses and reseat them?

Dodgy relay? Don't think the brake lights use a relay, but worth pulling a relay at a time, and check the fault again?

I had the handbrake warning light showing - the (!) light, and it turned out to be caused by a shorted filament in the brakelight, but still worked! So car electrics are mysterious things.

Have you checked out the cars owners club? Most let you join for free, or browse and search?

Good luck!

 

[hangman72]

thanks for all the replies. as i don't know too much about the wiring in the car i was a bit reluctant to mess around with it. i got a mechanic to look at it and it turns out that there was a break in the wiring behind the boot lid panel. only cost me 30 euro.
thanks again lads.