We have a 05 f650 running lights keep blowing fuse in plugged head light switch and ran a jumper wire to eliminate switch still blowing fuse unplugged main harness from out of firewall for headlight and running lights and still blowing fuse Im thinking has to be inside cab under dashboard

 

Welcome to FTE!

Keep tracing wires. What else can you do?

 

We've isolated it to the cab next thing we want to check his cab light wiring going up to the top we put circuit breaker in to help find short gets warm and hot even at times swapped relays around to see if it was a relay

 

Update wiring problem fix the ending up truck had lights on mirrors right door mirrors was cut and shorting out thanks for your help

 

An "easy fix" for once. Congrats!

 

Notice cab lights were dim