so what parts do i need to make one??
I have a couple of friends who are up on electrics and could help if i knew what to use.
What is the switch and what are the connector / clamps??
if you go this route be very careful,
the battery quick clamps are available from Halfords and i think maplins and most large auto, caravan and camping shops.
you need a heavy duty relay, as battery can pull a big load under strain of a hill.
the relay activates if the battery is connected correctly and connects the power, if the battery is reversed the relay stays 'open' (due to a diode) to stop the battery voltage reaching the control box.
the switch simply interrupts the relay coil and prevents accidental operation.
tbh not to hard but not a job for the uninitiated, blow the box and your in a world of pain.
if Karl (Boo Boo) has them in stock, i'd strongly recommend don't mess about re-inventing the wheel.
Karl's version has 'on - off - on & lights' in one switch.
Alan