making a latching relay from an ordinary 4 or 5 pin relay.

[Dave Adams]

This is a circuit for turning a relay into a latching relay.......

Why?

well you might want your fog lights to come on with your side lights (or dip) but when you switch off your lights the fog lights will trip off and not switch back on when the lights are turned back on.

the 12v supply for the momentary switch can come from ANY convenient place, once activated the relay will stay on until the side light are switched off.