Towbar wiring diagram for stilo needed

Although such a diagram may exist it is very unsual for tow bar installers (even Fiat Dealers) to use the manufacturers connections.

The current connection methods use a 4 or 6 way bulb failure, votlage sensing unit that takes a single +12V feed from the battery. It then uses sense wires to the rear light clusters (only take few milliamps) to switch relays to power the trailer/caravan lights from the main +12V feed direct fror the battery.

The voltage sensing loop measures the +12V voltage to detect that the battery is being changed and the engine is running to switch a spur 12V feed to the fridge circuit.

Quite elegant really. The oonly down side it that most installers use Scotch-Lock connectors to spur into the existing wiring often leaviing no room/loom length for repairs. Instead of tapping in many inches back down the loom they often tap in 1 inch (2cm) directly behind the light cluster connectors so when wiring problems occur one has no slack to manoever around the problem.

Nick ////

Can you tell me something more about "rear light clusters"? Is it just 6 rellays or some electronic? Do you know some producers? Resistance of inputs?