Here's a question of something I only realised yesterday when I started rewiring an old trailer I bought. When you wire up a trailer yourself, with the seperate light units permanently fixed on the trailer. They tell you to earth each light unit to the chassis of the trailer, as well as connect them to the earth wire in the 7 core cable. Which is the same as car lights were wired. But if you buy a light board, and I have one too. Then on those, all the light units on a light board are only connected to the earth wire in the 7 core cable. You don't have to wire those to the chassis each time you use a light board, which would make it very tedious and cumbersome if you did have to. So the question is, why do you need to wire the fixed lights on a trailer to an earth point on the chassis, as well as the earth wire in the 7 core cable?
Well done and thanks for sharing. I thought the trailer had to be hooked up to the car to allow the earth to work. Anyhow, I have put a new socket on the car as well as new plug on trailer cos it was beaten up. I didn't take note of where each wire was connected on the plug, and have a grey wire from the trailer... decided to double it up with the blue. I used a tester you can plug in to the car socket and trailer plug. It says there is a fault on trailer yellow (left indicator -- which doesn't work). So thought there was a break in yellow wire, but I tested for continuity from plug removing trailer left light cover and heard the beep, so apparently no break in wire. Am PUZZLED, BAFFLED... any ideas anyone? Thanks if you can reply!
