when using a 3 pin rocker switch for a fog light:
obviously earth is earth, but i have one connection from the live at my dashboard and another connection coming from my bulb at the back:
great diagram eh? 
i just want to be sure: does the bulb go to the load and the live from my dash is the supply? 
thanks
Hi.
There are two options depending on the type of switch it is. It could be either be a two position, three pole “changeover” rocker switch or an illuminated two position two pole switch with illumination.
If it is a 3 pole “changeover” switch. The middle connection is usually the “common” i.e. it is the supply and operating the switch to either of the two positions will connect the supply (common) to either of the two other connectors. In which case you just connect the supply or live to the middle connection with one of the other connections connected to the bulb in the fog light (the other being left unterminated). You can either connect the other side of the bulb to chassis earth or to the battery negative.
If it is a two position illuminated switch then yes as you say you connect the foglight bulb to the “load” connection and the “Supply” connection to a positive supply in your dashboard. The earth connection on the switch needs to be connected to earth to provide a circuit path for the illumination bulb in the switch.
Hope this helps.
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sorry, i should have said it was the 2nd one you mention.
as for the earth, you just connect it to any part of the metal frame?
eg near the gear stick?
thanks!
Yes. You need to screw it to the body metalwork near the gear stick or preferably somewhere near the switch on the metalwork behind the dashboard with a self tapping screw (or machine screw and nut) and washers. You may be able to find an existing screw nearby that will do the trick. Good luck!
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