Brake light problem!! Help!!

[nooneuknow]

I recently purchased a 2004 Land Rover Discovery. After being pulled over by a policeman shortly after, I was informed that my passenger side brake light was out which I thought was weird because I checked them out before I bought the vehicle and they worked fine. I went back home did some investigating and from realized what was going on:

With my headlights off and the brake pedal depressed, my passenger side brake light will turn on but doesn't seem as bright as the driver's side.

With my headlights on, the brake light bulb seems to shine normally when not in use but when I depress the brake, the brake light bulb goes off instead of getting brighter.

I've changed the bulb and the fuse but the problem continues and this seems to be the only bulb that is effected so I'm assuming the problem is a short in the wiring or I'm missing a connection somewhere connected to this bulb.


Is this a common problem others have seen? Any idea where the short may be before I start tearing down my Disco?

[Nero]

This is not an unusual problem and not just with landrovers. Most often you will see it on little used trailers that are kept outside. It typically means you have a bad earth connection for the cluster or the individual bulb, I'd start by pulling all the bulbs and cleaning both them and the connections white corrosion is conductive and will cause some interesting symptoms.
If you get not difference then I'd check the continuity to earth you may need a circuit diagram as some vehicles are earth switched ie you'll have power continuously on one side and the switch completes the contact to earth although this tends not to be the favoured solution as it means on the production line you have to run two wires everywhere.

Obviously its cheaper to run one, in my experience with Landrovers which is limited to a 89 110 this is not their practise but things may have changed between you vehicle and mine.


Brake light bulbs typically have two elements in them one is for the normal running/tail light and is around 5w and the other is for the brake and this is about 25w thus it burns brighter. They "should" operate independently of each other.