UK Car Repair: R reg Renault Clio break light failure, alex woods, bulb failure

Question
Hi John,

I am trying to sell my car at the moment but have run into some bother when I realised today that my break lights are not working. I have checked above the pedal to make sure the switch is not jammed, and have also checked the fuse, and even with a replacement fuse the lights would not function at all. I don't know whether you're familiar with the pre '98 Clio design but there are three lights, one below the windscreen wiper, and none are working, suggesting to me that it is unlikely to be a question of bulb failure. Do you have any idea what might be the problem, and can you suggest some other things I might have a look at? Thanks,

Alex Woods

Answer
I am unfamiliar with the Cleo, but very familiar with a test light. About $5 in the US so it should be about €3 in the UK.

Now, for your car in particular, by removing the tail lamp from the body and probing the wires in the back with the lights on you should be able to isolate which wire is dedicated to the brake lamp circuit. Have someone step on the brakes once you have isolated the circuit and see if the test lamp lights up. If it does, you need to check the harness connector for the tail lamp and its corresponding body ground. If not, you will need to unplug the connector from the brake lamp switch and test that. You can do that with the test lamp as well. Simply hook the wire lead to a ground point "anything that is bare metal like a bolt head or a shifter lever" and probe both sides of the connector. One terminal on the connector should light the test lamp. If it does indeed light even to a small degree, you can have a friend stand in back of the car while you use a paperclip or small bit of wire to jump the two terminals of the brake lamp switch plug. If you get brake lamps, you should only have to replace the switch. If all is lost and the power is no where to be found, you will need to get a repair manual and use the wiring diagram to chase the circuit around until you find the short.
However; if you find the need to start chasing power around you might want to conceder taking it to a shop and letting them find the short.  

Good luck and happy motoring.


John