I am a firefighter setting up my truck with high beam wig-wags. I bought a FS002 headlamp flasher from galls.com. To do the install in my 03 F250, I'm supposed to cut the passenger high beam feed and they say that there will be another wire in the harness that goes to the driver side high beam feed.

Is this accurate, that is, does the power go to the passenger side, and then run to the driver side, or the reverse?

I wish there was a manual that had the color codes for the wiring harnesses. I'd rather read about it before cutting.

 

Get a haynes manual, it should have a wiring diag.
Many vehicles have the head lights wired to the passanger side and the drivers side is tap from the passangers!