I’ve got a 2006 f150 stx it has the pull out fog light switch but doesn’t have the fog light bumper I was wondering if anyone has wired a light bar to this switch. Is there a harness already in there or do I need to run a wire all the way through? How many amps can I pull?

 

I don't have the answer for you, but that's a good idea....

 

I'm pretty sure the plug is up near the front of the frame, behind the bumper. The only snag is that the fog light circuit only powers up with low beam. When you switch to high beam, the fogs go off.

 

+1 on what P.Bronner Said. Fog light wires should be there, especially since you already have the switch. Check near the frame and the front bumper where the fogs would be on both sides, but I'd guess driver side. I'll check mine later tonight and give you a 100% answer.
Fogs will come on with parking lights and low beams when the switch is pulled out.
In regards to the low beam/high beam, most states it is illegal to run a second set of lights with your high beams unless it is the low beam lights. Also, in most states it's illegal to mount your fog lights above you head lights UNLESS they're amber. Also, check and make sure your LED's are DOT approved for on-road use and DO NOT say off-road use only. It sounds redundant, but it needs to be said.
Now is it enforced? Not really. But you find that one dick who's having a bad day...

 

There is a thread somewhere here called the "Bambi mod" that allows the fogs to work with the high beams. Very easy to set up.

 

Guess what..? You're right! I completely forgot about that. Good call.
I wish I could do that on my '13.