Here what happend:
Taillights went out on me last night, then 30 minutes later dash lights, the feed on the engine compartment fusebox was melted into the box, only the parking/taillight feed.


Here is what I did:
I remove the mess in the box tried to reset the fuses no luck,blows everytime.
I run my own wire,16 gauge, by pass everything, connect to taillights with 15 amp toggle and 10 amp inline fuse tthrough interior fuse box off 20 amp feed.
The wire gets so hot I cannot touch it.
Mind you... I have removed the stock feed, there is only my power supply.
I hear power drain on engine when I flip the toggle, seems unusual for just tail lights, tail lights are very dim...
Why is the wire getting hot?
Is 16 gauge to small?
What can you suggest?
I thank you in advance.

 

Have a look at the wiring on the headlight switch, and also the multifunction switch in the steering column. Both locations are know problem areas.

 

Check your grounds. There is something wrong. There shouldn't be melted wires at all.

 

+1 on HeyYou. I forgot about that.

 

If the wire is getting hot, you are drqwing more than 10 amps (rating for 16 ga wire). As well as checking ares mentioned, pull tail light housings and check the wiring back tehre to see if th wiring is chaffed or pinched.

 

One tail light is brighter than the other, I think I should start with the dimmer one and track the lines back to my feed.

I had installed some trailer lights about a month ago but I never had any problems until now, I used tapcons for my trailer plug so wires were seperated, I check the areas I used a test light on when I wired it up, nothing is melted there, so there was no crossover.
The problems started the night I had to pull my boat out of the water after dark and the one taillight on the trailer got wet at the boat ramp and went out, irritated me be cause they are suppose to be sealed
That night on the way home is when I lost all the lights.
I still do not see how that issue could shoot a short through the system so that it fried the fuse to the degree it did

When I started trouble shooting the first thing I did was disconnect the primary trailer plug feed to eliminate that as a source issue.
I pull this same boat trailer with my Eddie Baur Explorer and it never has lighting issues.

 

The make a harness that plugs directly into the tailight wiring on the truck, eliminating the need to cut, splice or tapcons. About $12, but never any problems such as you are having.

I foolishly let U Haul install some crappy 3 to 4 wire module on my Yota one time. After it melted itself later, it jacked up my lighting. U Haul will NEVER touch the wiring on anything of mine again........