Trailer Parking Lights question?

[PugtSounDav]

I had a couple of lights go out on my 2006 EZ-Loader boat trailer.
Two little parking lights along the fenders, one red, one orange.
Plus one of the big rear lights was going dim, only one LED out of the original 8 was still burning.
No big deal I thought, happens all the time. Turns out the big light was full of water. Go figure.

So, I stop by my local North River boat dealer to get the correct lights.
He just hands me a little red one, a little orange one, and 2 big rear ones. No charge!!!
Those North River guys are the BEST !!!!!!
He says that EZ-Loader changed the rear light style a little since 2006.
Might as well change both of the rear ones, so they match. OK, might as well.

First, I change the waterlogged rear light. New one works great.
But now, the old one on the other side that was OK, is dead. OUT.
Kinda strange. But, hey, I was going to change it anyway.
Change that one. New one works great. But now, the first new one is not working?
What's going on here? End up chasing a bad "floating" ground contact all over the place.
I cleaned and put dialectric grease on every connection that I could find on the trailer.
Which is a good thing anyway, since some of them were kinda green with surface corrosion.
I change out the little red and orange fender lights, and FINALLY, all of the trailer lights are working again!!!
HOORAY for me! So, I park the boat and trailer for a couple of days.
Next time I hitch up the boat. Not one of the six or so little orange and red lights will work. Not one!
The two big rear lights work when I step on the brakes, or use the turn signal, or put on the flashers.
But no night time running lights??? They WERE all working two days ago. What's up with that???

I've got a Chevy truck. Up under the hood is a big box with about 50 fuses of all different sizes.
I pull the one marked Trailer Parking Lights. Sure enough the 15A fuse is blown. I stick in a new one.
SNAP/POP! Right in my hand! I try another one, SNAP/POP again. OK that's enough for me.

Anyone got any suggestions???

[tanglediver]

A little green corrosion here, means it's everywhere! Trailer light wiring is doomed to suffer corrosion even more than the boat wiring,
and it is assembled with less care, also! Go, figure.
There is a system I go through, disconnect the trailer and boat and check the truck side. Good or no good. Repair as needed.
Still disconnected, check the trailer side with spare battery. Good or no good. Repair as needed.

When it comes time to rewire everything, assemble the wiring with proper care for full submersion in saltwater,
the best test for a wire mans work any where!

[lemaymiami]

Since I'm towing an EZ Loader more than 25,000 miles a year I've learned a bit about their new light setup (my 'new' one's a 2005...). Your system should have a plug in wiring harness and you're probably going to need a new harness, period. Once you have that new harness, pay particular attention to any point where the wires might become pinched or chafed, connect everything with the grease you're already using and you should sort out your problem. If you're submerging your trailer (something I try to avoid if at all possible) the slightest break in the insulation means eventual failure - usually up inside where you can't see it.

I'd try to get the exact harness from EZ Loader since it will already come with all the various plug in points, ready to go. If you have to use a generic harness (or make your own) you'll be in the business of splicing in at every light junction, lot's of opportunity for trouble. Good luck, hope this helps.

[lemaymiami]

Just re-read your original post and forgot to spell something out about any trailer harness and blown fuses... Once I pop a fuse and the replacement fuse pops too, I know I've got a dead short somewhere in the wiring harness - usually a break in the insulation somewhere that allows the wire to ground out on the frame. The first place to check for that is the tail lights, check to see that the wires weren't pinched up against the frame when you re-secured them. That's where my breaks are usually found ( two or three times in the last fifteen years).... Your wiring harness may be sound with only a minor break somewhere. You'll know you've found the problem when you repair a break then install a new fuse with your trailer hooked up to the tow vehicle. If it holds you're in business. I keep a supply of those 15 amp fuses on hand....