Trailer wiring issue

noway2

noway2

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Help request. The other day, I was hooking a utility trailer to a new vehicle and unfortunately the hitch ball was too small. I put the mower on the trailer tongue went up and pulled the wires out of the connector (which my parents threw away)

Ordered a new connector, wired it per my understanding of the diagram for a utility (not RV) but no functionality. It acts like a missing ground ???

Pictures attached. What am I missing. The red wire was cut at the factory. There is no white wire. Just blue, black, brown, yellow, and green.

Per the diagram, it's pretty obvious which is the top and bottom of the plug.

Edit to add, I don't think I did anything stupid like getting insulation under the lug to where the wire isn't making contact, so I'm going to assume something else is incorrect.

IMG_0863.jpeg

IMG_20240501_174828267_BURST000_COVER.jpg
 
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And it was working prior to the incident? I think it’s a ground issue as well. Never seen one without a ground.
 

The Trailer Wiring Diagram and Connector Application Chart​

Trailer Wire Color Codes – Colors Coordinate With Trailer Wiring Diagram
Connector StylePinFunctionColorDescription
7-Pin6-Pin5-Pin4-Pin1GroundWhiteGround for all trailer electrical functions.
2Tail Lamps
Running Lights
Side Markers		BrownPower for all normally ON lamps.
Tail, Running & Side marker lights.
3Left Brake Light
Left Turn Signal		YellowMulti-function signal for the
Left Side Rear Tail Lamp
4Right Brake Light
Right Turn Signal		GreenMulti-function signal for the
Right Side Rear Tail Lamp
5BrakeBlueElectric Brakes Control Power
or Hydraulic Brake Disengagement (5-Pin only)
6BatteryRed
(or Black)		Vehicle Power +12V
For trailer battery charging and accessories.
7Back UpPurpleBack Up Lamps on Trailer Tail Lights
/ Hydraulic Brake Disengagement


mechanicalelements.com

Trailer Wiring Diagram – Lights, Brakes, Wire Connectors, & More

Need a trailer wiring diagram? These wire diagrams show electric routing for trailer lights, brakes, aux power, breakaway kit, and connectors.
mechanicalelements.com mechanicalelements.com
 
black is ground.
Check the fuses in your tow vehicle. I had that happen once and blew a couple fuses
 
Hook the trailer to the ball and let that connection be the ground and see what you have.

Seems apparent blacknis ground
 
Burt Gummer said:
black is ground.
Check the fuses in your tow vehicle. I had that happen once and blew a couple fuses
Click to expand...
I was thinking I could possibly test that with a volt meter too. Put the negative on the black and then check lights and turn signals. The remaining wire would be the brake feedback.
 
Also the red wire is to charge a battery in an emergency disconnect box if the trailer is equipped
 
LeeMajors said:
Hook the trailer to the ball and let that connection be the ground and see what you have.

Seems apparent blacknis ground
Click to expand...
It was hooked up but that didn't make the connection. I'll check it in the morning.

Burt Gummer said:
Also the red wire is to charge a battery in an emergency disconnect box if the trailer is equipped
Click to expand...
That makes sense. It does (or did have a functional) breakaway cable, and I wondered about the battery power for it. Guess not since they cut out. There is a box that looks like it could be a battery but never looked into it
 
Jeppo said:
Can’t you verify which is ground using a VOM with one probe on the chassis?
Click to expand...
Excellent suggestion. Sometimes you get mired in the weeds and can’t see the forest for the trees. A quick continuity check will verify that and prevent a blown fuse.
 
Is there a white wire (or other color) connected to the trailer anywhere, could be hooked to a bolt or screw, run into the metal of the trailer near the tongue?
On a couple of my trailers, that is how the ground is run. It is just a wire that comes out of the connector and into a screw or bolt on the trailer.
If it got disconnected with the rest of the wires, you might not notice it laying there or it could have been partially ripped off and stayed with the connector that got thrown away?
 
DangerRuss said:
Is there a white wire (or other color) connected to the trailer anywhere, could be hooked to a bolt or screw, run into the metal of the trailer near the tongue?
Click to expand...
Not that I’ve noticed, but it’s worth a second look. If a DMM doesn’t verify that the black is ground, that might be something to check into.
 
DangerRuss said:
Is there a white wire (or other color) connected to the trailer anywhere, could be hooked to a bolt or screw, run into the metal of the trailer near the tongue?
On a couple of my trailers, that is how the ground is run. It is just a wire that comes out of the connector and into a screw or bolt on the trailer.
If it got disconnected with the rest of the wires, you might not notice it laying there or it could have been partially ripped off and stayed with the connector that got thrown away?
Click to expand...
Here are example pics from 3 of my trailers. You can see that the ground wire just connects to the frame on the tongue. Look for a bolt or screw where it might have been, and sometimes the ring terminal from the wire would still be left on the bolt.

IMG_9559.jpeg

IMG_9560.jpeg

IMG_9561.jpeg
 
@DangerRuss I looked at the connections but don't see a ground jumper to the chassis, though it's obviously bonded somewhere.

@LeeMajors and @Burt Gummer you guys called it, the black was the ground. We found the old plug and it had copper pieces stuck under the terminal that said 'white' (same position as the replacement). Used a DMM and saw a dead short to a bolt in the chassis from the black wire. Others showed some small resistance, reading through a lightbulb. Moved the black wire to the ground lug, plugged it in and the brake controller went from NC to .C and started reading numbers when you depressed the brake. Checked the tail lights and turn signals, all good.

Thank you everyone for the help. I appreciate it.
 
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What you have isn't standard but that's ok as a lot of trailers vary a bit. One can make any function any color, including the same color. That does pose a problem for the next person who has to fix something.

Here are the Traditional SAE Trailer Wire Colors
th-1.jpeg

For more info:

ISO standards for trailer connectors - Wikipedia

en.m.wikipedia.org en.m.wikipedia.org

Glad you got it fixed!
 
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rdinatal said:
What you have isn't standard but that's ok as a lot of trailers vary a bit.
Click to expand...
Except for the black / white issue, got lucky. Everything else was per standard. I did notice, just barely, a white wire in the mass of butt jointed wires where the manufacturer spliced everything together. I suspect they got a cable that almost matched and spliced the white (ground) to the back, but it would have been a chore to try to separate it all.
 
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