hi, ive just fitted a towbar to my astra sri 2003, when i came to the electrics bit i dint know what to do, the instructions with the tow bar only tell me what the wires from the trailor connect to not what colour my astra wires should be, i would of thought the wires matched up but they dont as i have a fair few different colour wires in my astra compared to the trailor wires, does anyone know where i can get a wiring diagram from so i know what my astra wires are ? thanks