Sparks at Hitch

[FishingKY]

Hi all, it's been a while.

I just hooked up my trailer to the truck (2015 F350) and here is what I noticed...

1) trailer lights did not work at first
2) after going down my 1000'+ driveway they started working.
3) when I got home I noticed the safety chains would spark when I would rub, slide, across the hitch.
4) The lights would not work when plugged into the 7 round to 5 flat adapter and the trailer was not connected to the truck.
5) Reverse brake cutoff did work when trailer was on the hitch

Questions are...
1) I thought with the 5 flat connector the ground went through the trailer wiring connection and not the ball to the trailer. is this not correct?
2) why would the safety chains spark when slid across the truck's hitch (after wire plugs connected)?

[2fish]

Trailer has a hot wire rubbing the frame

[fishnfireman]

My first thought is your trailer side ground isn't making good contact.
Its possible theres a bare hot wire rubbing. but that doesn't account for the lights working after pulling a short distance.
Also you would normally have blown that fuse in short order.

[Bassman Ia.]

My thought is a grounding issue

My trailer lights will not work unless the trailer is on the hitch ball, or a jumper wire running from the truck to the trailer.

As far as the sparks—— When I was still working pulling doubles ( semi trailers). We got new convertors ( the 5th wheel that goes between the trailers). Those convertors had two light cords. One light cord plugged into the front trailer, the other light cord plugged into the back trailer. There were times the lights on the back trailer would flicker, or not light up. Sometimes we would see the safety chains spark when hooking them up. So we knew it was a grounding issue, not a hot wire issue.

[CatFan]

Grounding issue. White wire isn’t connected somewhere.

[CatFan]

Trailer has a hot wire rubbing the frame

Fuse In the truck would blow instantly if this happened

[krindgen]

My first thought is your trailer side ground isn't making good contact.
Its possible theres a bare hot wire rubbing. but that doesn't account for the lights working after pulling a short distance.
Also you would normally have blown that fuse in short order.

Using the hitch as the ground. That's all. I bet you've got a jointed tongue? MarineMaster has this issue on their trailers if the ground isn't real good. Lights will start working when you have some weight on the hitch which causes the jointed tongue to have good continuity through it.

[FishingKY]

krindgen... yep, that's the trailer I have.


Thanks everyone for the replies. Based on the answers given I'm going to go through the trailer wiring and redo all the connections, paying extra attention to the grounds. I checked my relays and fuses and nothing is blown.

Should there be a ground wire inside each tail light, from light frame to trailer?

If it's a ground issue that could explain why when going a short distance any corrosion on the jointed tongue or on the receiver ball is worn through using the ball as the ground. Am I correct in thinking that with a 7 round to 5 flat the grounding should be through the wiring connections (everything should work even if boat is not on the hitch...just plugged in).

[digthemup]

FishingKY

I have a bass rig and a small boat with trailers. My EzLoader is grounded from the plug to all the lights, but the smaller 1 the rear lights are grounded to the frame of trailer. Crazy thing though, the lights on both only work when they are hooked up to the truck, so that must close the circuit, even when the ground shows continuity when I test it.

[PJ-Rohlf]

krindgen... yep, that's the trailer I have.


Thanks everyone for the replies. Based on the answers given I'm going to go through the trailer wiring and redo all the connections, paying extra attention to the grounds. I checked my relays and fuses and nothing is blown.

Should there be a ground wire inside each tail light, from light frame to trailer?

If it's a ground issue that could explain why when going a short distance any corrosion on the jointed tongue or on the receiver ball is worn through using the ball as the ground. Am I correct in thinking that with a 7 round to 5 flat the grounding should be through the wiring connections (everything should work even if boat is not on the hitch...just plugged in).

I think marine master might ground through the safety chains too. Had times where I hooked everything up, no lights, wiggle the chains on the truck where they connect and boom lights work

[CatFan]

I think marine master might ground through the safety chains too. Had times where I hooked everything up, no lights, wiggle the chains on the truck where they connect and boom lights work

That’s a symptom of bad wiring, not a feature.

[krindgen]

I think marine master might ground through the safety chains too. Had times where I hooked everything up, no lights, wiggle the chains on the truck where they connect and boom lights work

I've had some guys suggest adding a ground from the frame, through the jointed tongue, and into the plug to make sure there is good continuity all the time. I guess not a ground, but a jumper. Gonna do this in the spring. The chains, it's the same things as the ball and tongue. I've seen a small blue spark sometimes on mine when hooking up.

[fishnfireman]

That’s a symptom of bad wiring, not a feature.

The white wire is supposed to be the ground.. Make sure it has a good clean connection (to the frame). Yes it's a good idea to not attach it on the swing away tongue..

[FishingKY]

I looked at it quickly when I went in the garage today. The ground is connected at the front section of the tongue. When I go through it I will do the "jumper" idea as well as redoing all the connections. While I'm at it I'm adding LED reverse lights.

[fishnfireman]

Good luck.

[PJ-Rohlf]

That’s a symptom of bad wiring, not a feature.

Neat on a year old trailer isn't it.

[1BADAIR]

The ball or chain should never be the ground. 4 5 or 7 way all have their own ground wire

[FishingKY]

Update... Ran a "jumper" wire from the front part of the swing away tongue to the fixed section of the trailer to provide a constant ground and it fixed the issue. Thank guys for the help in getting this aggregation fixed.

[Moneyshot]

I think I'm going through the same thing to revamp this old thread. Same deal, my trailer will only light when i jiggle safety cables. My ground wire on trailer is to bottom of reverse solenoid, should I jump one back towards the rear across the swing tounge?

Trailer is marine master with Gator hide some i guess i will have to clean a spot to attach new ground?

[billnorman1]

I think I'm going through the same thing to revamp this old thread. Same deal, my trailer will only light when i jiggle safety cables. My ground wire on trailer is to bottom of reverse solenoid, should I jump one back towards the rear across the swing tounge?

Trailer is marine master with Gator hide some i guess i will have to clean a spot to attach new ground?

Yes. Use white wire, paint over the bolt after you install it on a clean, ground down spot. You could also use a lock washer under the bolt terminal lug.