Swap the relay with one that does work(eg headlights or running lights) and see what happens
I would think if that doesn't work and the light on the button does come on when it's pressed then the switch is bad
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Also don't forget the 02 has to at least have the running lights on for the fogs to work
I would think if that doesn't work and the light on the button does come on when it's pressed then the switch is bad
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Also don't forget the 02 has to at least have the running lights on for the fogs to work