Trailer Harness: Don't think that's it anymore. I found the wires for turn signals and what-not that would go to the trailer all wrapped up and off to the rear driver's underside of the truck. We unwrapped them up to the last couple inches and all looked good.
The wires that are direct feeds from the battery and for brakes are the only ones by the hitch.
I have (with 99% certainty) determined that it is the left blinker that is shorting it out. Using right blinker only and the fuse has lasted more than a day now - havn't used left blinker since yesterday morning trying to test this out.
Next step is to buy a telescoping mirror... I unwrapped the wires again that are behind the hitch - what I "jiggle" and tape to the tailgate and the fuse works again for a while - what I could get to looked fine but then some genius decided to "thread" the wires into and thru the tailgate and they go towards (I assume) the area between the bottom of the body of the truck and the top of my gas tank. I'd love to be able to get the section that goes thru the tailgate out to take a look at the wires even though the casing looks good.
Trying to follow the wiring diagram in the Haynes book is proving to be a little challenging for a newbie but I will take a look up at the front too as mbumgua suggests.
muff34... light housings? I'm trying to remember what the taillights looked like when we had them apart looking at the bulbs... this is where you talking about right?
signal light flasher... I think this was replaced January 2006 at a national tire chain - I mentioned this earlier in this thread. It's located behind the driver's side dash somewhere right? Is it similiar to a fuse in that it will be easy to see if it's bad?