Fog lights won't work

[Eluding]

I thought it was my switch, so I bought a brand-new GM switch. The fog lights still do not turn on.
At both switchs I have power at the brown, gray and purple wires. When I jump the purple wire to the purple with white stripe wire both fog lights do come on. So I know that with power the lights work.
Did I just get a bad new switch? Or is there something else I'm missing?
Thanks.

 

[GM TURBO]

Do you have the regular lights turned on as well?

 

[Eluding]

Yes, the headlights are turned on when I try to turn on the foglights.
The fog lights turn on when I use a jumper wire to connect the purple wire on the switch harness to the purple with white stripe wire in the same harness. However, neither the old switch nor the new switch will activate the fog lights. Seems odd to me that the new switch won't work.

 

[GM TURBO]

Hmm..

Dunno if there is a fuse or not. I would think there is - or some sort of relay. I don't have a wiring diagram to check it out for you. I just wanted to make sure we checked the obvious.

The switch, on a working truck, lights up when the fog lights are turned on. Is yours doing this?

 

[BillC]

Try disconnecting the switch and checking its continuity, both off and on. Should read infinite resistance with the switch off and almost-zero resistance when on. If the switch is okay, check the plugs/connectors for the switch. It is possible one of the clips is bad/broken/corroded.