Thread: Fuel Gauge Over-reading

If the headlights on/off change the reading, it is a certain indication that the problem is earthing of the gauge. Now this problem may be at the gauge itself, the instrument cluster, or the body to chassis or chassis to engine (this depends on where the battery is earthed, chassis or engine).

There is no voltage regulator as such, it is in the gauge, but this depends on the gauge being earthed to work, so a faulty connection anywhere between the battery negative and the frame of the gauge will affect it. Your replacing the battery lead at the same time may be coincidence, or you may have disturbed something without noticing - for example, did you manage to leave off another wire attached at either end of the earth lead? Or bump something?

John

Thanks mate. The battery lead goes to the chassis but on the way it also attaches to a little bolt on the inner wing behind the battery just in front and below the engine fuse box (there's a metal tag on the cable which bolts up to it). There are other earth wires attached here too. I'm thinking this may be the problem, a bad connection at this point. Surely this little tag isn't the only earth between the body and the battery though?

Originally Posted by Traco

Thanks mate. The battery lead goes to the chassis but on the way it also attaches to a little bolt on the inner wing behind the battery just in front and below the engine fuse box (there's a metal tag on the cable which bolts up to it). There are other earth wires attached here too. I'm thinking this may be the problem, a bad connection at this point. Surely this little tag isn't the only earth between the body and the battery though?

Very likely! And if it is, then that is probably the problem. I must admit I am not very familiar with Discoverys, but your problem is simple electrics.