There's a thermal cutout built into the headlamp switch. It tries to reset automatically because it's a safety issue. Sometimes the contacts get pitted and cause a little resistance. Resistance causes heat which leads to the cutout.
Adding plow lights adds to the problem if the truck's lights don't turn off when the plow lights are on. Aftermarket fog lights add a lot of current load to the switch. Factory fog lights are run by a relay.
When you pull the switch out, look for signs of a melted connector, burned terminals, or overheated rivets on the switch's terminals. Overheated terminals can be cut out of the connector and replaced. You don't have to replace the entire connector body. You will need to cut the wire(s) back far enough to find shiny copper. Splice on a new piece of wire and a new terminal and solder all connections. I prefer crimp-type quick connectors, but I solder them too after they're crimped. Be sure the terminals fit tightly when plugged in.
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Saturday, April 25th, 2009 AT 3:30 AM