Trailer to Truck electrical connection

cranker789

Need some advice on how to improve the connection between my truck and trailer lights. I find that it's not always a good connection and the lights don't work on my trailer every time. Is it a good idea to use dielectric grease before a trip, my trailer uses the 4 pin connector. 

Thanks.

Soda Popinski

i find that 90% of the time it's the ground wire that is the issue.   So here's what i did.  I rewired the trailer with an extension cord from Ace Hardware.   More durable than those little trailer wires that come in the kit, and they have a dedicated ground.  I also mounted the lights on the guide on posts so there are no connections under water.   Since I did that, i have had exactly zero issues with trailer lights whatsoever.  I have done this to two trailers and if i trade up and go bigger i'll do it a 3rd time because once it's done...it is DONE.    Hope this helps.  

MelbourneMark

Like he said; run a dedicated ground.  I too used an old extension cable and mounted high on guide posts.  That lasted for years without issue.  My new rig has another extension cable but mounted the normal low spot.  I just had my first light failure, but it wasn’t the wiring.  

Basically run a 3rd ground wire to each light however you can. Heat shrink butt connections and or caulk the connections 

livebait1

What they said-dedicated ground, lights on guide-ons, no breaks in wire between lights and plug ins. Been good for 6 years.

Alex from GA

When I had a mostly salt water boat I used removable lights all the way to the truck.  I bungeed them to the boat and just unplugged and rolled up the cable when I launched.

conchydong

I used to use a old jumper cable to hook to the trailer and truck for a ground.Never failed me

Gotsea

As they say ground is the culprit 99% of the time, I use submergible LED lights with marine wire good for  6 years so far  

pottydoc

What a bunch has already said. Dedicated ground. The easiest way to
do it is the way Soda did. Buy a couple (or one long) 14 wire cords, cut off the connections, and run down each side of your trailer. Wire the white wire to
the ground on the light, the black to tail lights, and green to the yellow wire on one side, and the green on
the other. On the other end, wire both white wires to the white on
the pigtail, both blacks to
the black, one of the greens to
the yellow wire, and the other to the green wire. Use heat shrink on all connections. 

CapnSkip

Cranker, you need to first verify if the problem is with the wiring on the trailer end or not. Is the trailer harness on your truck  factory installed or was it spliced in afterwards? Assuming it is factory, then you might want to look at the receptacle where the round 7 way connector plugs into and make sure that's all clean along with the adapter. If it was added on, then make sure all the connections where it's spliced into the tail light wiring are solid. Dielectric grease could be a good idea but I don't think you would need to use it every time you use the trailer. If that all appears to be good, then like the other comments stated,check your ground connection to the trailer frame. If the trailer has some years on it and the wiring is starting to look old, this may be another option:

https://www.etrailer.com/Wiring/Optronics/A35W42B.html

c62dkzrv

When I had a mostly salt water boat I used removable lights all the way to the truck.  I bungeed them to the boat and just unplugged and rolled up the cable when I launched.

As they say ground is the culprit 99% of the time, I use submergible LED lights with marine wire good for  6 years so far  

Gotsea

CapnSkip said:

Cranker, you need to first verify if the problem is with the wiring on the trailer end or not. Is the trailer harness on your truck  factory installed or was it spliced in afterwards? Assuming it is factory, then you might want to look at the receptacle where the round 7 way connector plugs into and make sure that's all clean along with the adapter. If it was added on, then make sure all the connections where it's spliced into the tail light wiring are solid. Dielectric grease could be a good idea but I don't think you would need to use it every time you use the trailer. If that all appears to be good, then like the other comments stated,check your ground connection to the trailer frame. If the trailer has some years on it and the wiring is starting to look old, this may be another option:

https://www.etrailer.com/Wiring/Optronics/A35W42B.html

Using dielectric grease is not a good idea in any electrical connection, because it is a none-conductive grease, hence the name "DIELECTRIC" if you want to improve conductivity you have to use something like BURNDY PENETROX-A, dielectric can be use on waterproof electrical connectors to keep water and moister out by applying to the rubber  seal. also if you don't use tin plated marine wire, it will crap up shortly if submerge in the water at boat ramp.   

Tarpon Monoxide

cranker789 said:

Need some advice on how to improve the connection between my truck and trailer lights. I find that it's not always a good connection and the lights don't work on my trailer every time. Is it a good idea to use dielectric grease before a trip, my trailer uses the 4 pin connector. 

Thanks.

Does your truck have one of those round connections on the truck back bumper to connect trailer light connections?