[BrickPig]

If it's a factory fog light switch there are 4 wires going to the switch. I wish I knew what each wire does...

Maybe the foglight relay is bad? When you turn on/off the foglight switch do you hear the relay clicking?

 

[BrickPig]

What is the Factory Fog Switch part number? Does any one know?

Scion xB 2008-present OEM fog light switch p/n is 84160-12060 and costs about $55 shipped