audi a4 towbar fitting help

[fisher72]

fitted a Thule detachable tow bar to my 2004 Audi a4 1.8t got the tow bar fitted lot of messing but got it done then it comes to the electrics fitted the relay unit as it said the only problem i have is no brake lights on caravan on instructions for Audi it says side light night light and brake light all run of 1 wire this is were I'm lost wired it up as it said leaving black and brown wire off but no brake lights totally stumped help please

[BMurr]

is it a new kit? If not check the plug connection for corrosion. Give the plug a few pulls in and out of socket and put a bit of sideways stress on it when you do so that the connections will get a bit of a scrape and come clean. Also worth checking the bulbs. I guess if you have access to another car with known good electrics then plug it in to that and see is it a fault with ther caravan or your car. If it is your car at fault you will have to go through all those connections again to see of Ok, especially if you have those blue piggyback connectors as they can sometimes not make the connection.