UK-POLOS.NET - THE VW Polo Forum

Hi all, new to forum needing some advice. Got a 3rd brake light warning on dash, once I eventually worked out how to get spoiler apart, ordered a replacement online. Took old one off fitted new one, same issue. Tested the lines to light and no power. Stumped from here, where do I look next? Trying to avoid garage costs if I can fix myself without too much effort.

Normally, if the removed high level light still works okay when connected to a 12V DC source, and shows no evidence of rusting due to water getting into it, the problem should be either the ground lead or the 12V DC supply lead, and that normally means that the wire(s) have failed at or near the protective rubber sleeve area where the wires get flexed every time the hatch is opened or closed.

Try, with the hatch open, to squeeze the rubber sleeve and see if you can detect a break or other weakness in one or more of the wires that are in that rubber sleeve, after that if you find nothing unusual, then you need to remove the new high level light and check to see, using a DVM which of these two wires are damaged, ie is it the 0V ground or the 12V DC that is missing when the ignition is on and the brake pedal pressed down.

If you have found out which one it is, then you will need to remove some panels to locate the wire break location, cut the wire and solder in a repair section and cover it with heat shrink sleeving, just one bit of advice, aim to keep the ends of the repair section either inside the body of the car or inside the hatch and NOT within the area that gets flexed when the hatch is opened/closed.