DespresWest

I bought my 2002 S430 last year and it had an intermittent fault in the left brake light where it would flicker from time to time but mostly when it is humid or rainy. Now the light is out more often than not so I think that it should be easier for me to chase it out. Any hints or advice you can give me on this problem would be appreciated.

tusabes

Get some used lights cheap off eBay

DespresWest

It's not the light itself, since it still works sometimes. I'm pretty sure that the problem is electrical.

VMAX7

If you ever need replacement LED light circuit boards for the taillight let me know, ive got a few for either side.

wallyp

I would start by cleaning and checking the contacts in the taillight unit, including the ground (earth) contacts and connections.

DespresWest

That would be the wire harness right next to the light itself right?

Thanks

DespresWest

No joy. Does anyone have a wiring diagram so that I can try to chase the fault?

DespresWest

I checked the bulb, tried sanding down the contacts, and replaced the plug but the light still doesn't work. It can't be the whole wire harness because my reverse and turn signal lights still work. I'm kinda lost as to where to go with this now. Any help would be appreciated.

tusabes

try this

wallyp

For the bulb to light, you need power to one bulb contact and a ground (earth) contact on the other bulb contact. Get a 12 volt test light (cheap) at any auto parts store or department.


Attach the alligator/crocodile clip of the tester to bare metal on the body. Get a helper to apply the brakes. Make sure that the other brake light is on. Test the harness connectors to see if one of the connectors has power. If so, you probably have a poor ground/earth connection. If neither connector has power, and you are certain that you are using the tester correctly, the circuit might have a broken wire or connection.

DespresWest

Yeah I was going to try to pin down the electrical fault next. I picked up a cheap multimeter and now just need to get some time to have a friend help me out. I hope that I find something cheaper than having to replace the whole light assy but fear that it is the wire harness coming out of the car.

wallyp

The key here is to remember that a problem with the ground/earth circuit is just as likely as a problem with the power circuit.