Trailer Lights

[Huntindave]

Originally Posted by DW

There is a separate ground wire from the vehicle that connects to a ground wire on the trailer via the plug, but isn't anymore likely to fail than any other wire ,and if it shorts to the trailer the trailer is already grounded so no problem. I doubt it is a ground problem.

I would wager than a great percentage of small trailers on the road today, do NOT have this ground wire even hooked up. One way to check to see if you have a GOOD ground is to plug your trailer lights in WITHOUT hooking the trailer up to the hitch ball. If you have a good ground wire, all the trailer lights will still work and work properly. If they don't work with the trailer unhitched, then yes, you have a ground problem.

[DW]

All the 4 wire and 7 wire sockets on contemporary vehicles have a dedicated ground wire. The plugs on the trailer side also have them.

However, if the fellow has a trailer that requires ground to the vehicle via the hitch ball, then ground continuity possibilities increase. If that the case replacement of the trailer wiring harness is the way to go with a ground wire that extends to each light, with something like http://www.amazon.com/Invincible-Mar...r+wire+harness

If his vehicle and trailer have modern wiring, then a connection failure or ground fault on the + side is most likely the cause of his problem, and if there is a fault on the + side on the trailer with wire touching the trailer frame, a vehicle fuse is likely blown, too. That is the reason a testor is helpful.

If the trailer does not have electric brakes, then there should be 4 wires running from the trailer wiring plug.

[Huntindave]

Originally Posted by DW

All the 4 wire and 7 wire sockets on contemporary vehicles have a dedicated ground wire. The plugs on the trailer side also have them.

However, if the fellow has a trailer that requires ground to the vehicle via the hitch ball, then ground continuity possibilities increase. If that the case replacement of the trailer wiring harness is the way to go with a ground wire that extends to each light, with something like http://www.amazon.com/Invincible-Mar...r+wire+harness

If his vehicle and trailer have modern wiring, then a connection failure or ground fault on the + side is most likely the cause of his problem, and if there is a fault on the + side on the trailer with wire touching the trailer frame, a vehicle fuse is likely blown, too. That is the reason a testor is helpful.

If the trailer does not have electric brakes, then there should be 4 wires running from the trailer wiring plug.

Go to your local Auto parts store or Walmart and look at the package. The wiring "harness" will have a 12 inch stub wire for the ground . That will not reach to all the trailer lights. Therefore what do folks do? They fasten that stub wire to the trailer tongue.

Yes a new trailer with factory wiring MIGHT just have a full length ground wire running to each light but guess what,,,,,,,,,,,,,,,,, the new trailer I purchased last fall to haul my ATV did not! That is the reality of the situation.

[Hot Runr Guy]

Originally Posted by Huntindave

Go to your local Auto parts store or Walmart and look at the package. The wiring "harness" will have a 12 inch stub wire for the ground . That will not reach to all the trailer lights. Therefore what do folks do? They fasten that stub wire to the trailer tongue.

I've decided that rather than using a round-7 to flat-4 adaptor, I'm just making my own harness using a round-7 connector, and since it has screw-terminal connections, I run (2) whites (ground) and (2) browns (running/tail) all the way to the back of the trailer.

Using tinned #16awg wire, both wires fit nicely in a 14-16 #8 ring terminal, then screwed to the round-7 insert. Put a little shrink sleeving on the terminal below, and you're done.

HRG

[DW]

Originally Posted by Huntindave

Go to your local Auto parts store or Walmart and look at the package. The wiring "harness" will have a 12 inch stub wire for the ground . That will not reach to all the trailer lights. Therefore what do folks do? They fasten that stub wire to the trailer tongue.

Yes a new trailer with factory wiring MIGHT just have a full length ground wire running to each light but guess what,,,,,,,,,,,,,,,,, the new trailer I purchased last fall to haul my ATV did not! That is the reality of the situation.

I see what you are saying.

For those with trailer light trouble without complete ground wiring, consider replacing the existing wiring with a full ground wiring harness like referenced above. Or splice a white ground wire extension(s) to the "stub" and wire directly to each trailer light. Using the trailer frame as the lighting ground is asking for lots of ongoing trouble.

[REW]

TINNED WIRE

When replacing trailer wiring, use Tinned wire:

http://www.ebay.com/itm/Seachoice-13...ac99d1&vxp=mtr

Basically this is wire that has been tinned, before insulating. The use of "tinned" wire in trailer wiring prevents the intrusion of "black wire corrosion".

Perhaps you have worked on outdoor marine or damp environment wiring and have found that one or all of the wire conductors have turned black. If so, you are seeing the effects of black wire corrosion. Black wire corrosion seems to be especially bad in outdoor DC powered wiring on the negative wire. For some reason the black wire seems to attack the ground side of DC circuits more often than the + side of DC circuits.

In the case of black wire corrosion, you will find "black wire" when you strip off the insulation of a conductor that should be copper colored.

Black wire corrosion has attacked the wire, and you need to continue to strip back the wire's insulation, until you find no more black wire. You may find that the full length of the wire is black and in such case the entire wire needs to be replaced.

When the wire turns black, the wire has turned into a non conductor. The wire almost looks like a piece of burned toast and it conducts electricity about as well as burned toast.

The best solution for black wire corrosion is to use "tinned" insulated wire for outdoor potentially damp wire installations. The tinning of the copper wires, completely prevent the "black wire corrosion."

Take care