Leaderboard

Looking at the OEM wiring diagram Pin 12 Blue wire goes to the Alternator D+ terminal Pin 21 Blue wire goes to drivers door open switch Pin 29 Blue/Brown wire goes to Handbrake switch & Low brake fluid switch

Thanks again for your very comprehensive response. Clearly it is important to check the quality of the brake fluid. However, using a tester that costs £2.49, including postage, is unlikely to give me confidence in the result! How can anyone make money out of selling what appears to be a complicated bit of electronic wizardry for such a low price. Postage alone will eat up half that, then there’s the manufacture in China, shipping to UK, packaging, etc. where’s the profit for the UK seller? You’d be hard pressed to buy a biro for that money! Nevertheless, I am tempted to buy one and try it out on all three of my cars, just for the fun of it! On the subject of leaks, amazingly the car does not leak anything at all - oil, coolant, brake fluid, etc - judging by the cardboard on the garage floor! Of course, it is possible that there is a small seep into the rear drums, causing loss of friction. To be investigated. As for Boyles law, I thought that applied to gases. As I understand it, the problem with water in the brake fluid comes when it gets very hot and boils. I doubt that this will ever be the case with my exploits in the Polo, and certainly not for the leisurely short journeys it is currently used for! Rust is a different issue, so testing is a sensible precaution. Thanks again for your thoughts on this subject. c