The previous owner DID splice directly into the tail light wires. He came off the wires going to the taillights and split the wire going to the 7 pin and the pigtail. The tail lights are fine with dielectric grease on them. Checked them again today. I'm thinkin I'm going to have to rewire the 7 pin. There are 3 plugs trying to be run off of the tail light wiring, a pigtail, a 7 pin and a gooseneck plug in the bed of the truck. That is probably too much stuff hooked in!

 

Figured it out guys! Thank you to everyone who responded to my first post on this site. The previous owner had spliced the trailer tail light hot wire to the running light(top bulb on left truck tail light). The top bulb would illuminate with the truck brake light when the brakes were applied as long as I had a good fuse in #46 fuse socket. I am not smart enough to know why this would cause the lamp out alarm to come on as the trailer light would work as designed along with the two bulbs as described above. No worries though, I seperated the 2 wires and life is good again! Thanks again guys. This site rocks!

 

If someone taps the truck's tail/turn/brake lights to provide juice for the trailer lights, the computer will sense the drop in voltage and throw a "lamp out" warning on the instrument cluster. You could get away with that on older pickups of course, but not anymore. Trailer lighting is a separate circuit now.

So... with a splice I predict you're going to get "lamp out" again the next time you hook up a trailer and use the lights.

(BTW, the Modulite gets away with it because it only senses voltage being applied to the tail/turn/brake lights, it gets the juice direct from the battery)