Need Help with Trailer Plug

[sqiggy]

I’m not a electrical guy.
So, I haven’t hauled my trailer in a while. Picked up another 4 wheeler since my other one burnt to the ground last year and now, none of the lights are working. I think I have it narrowed down to the truck plug. First, I checked all the fuses. Then I replaced the 7 blade to a 4 flat plug. It even has test lights on it but none have lit up. How can you check the truck plug to be sure?

[basskicker24]

Check the ground on your trailer plug.


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[andre3k]

Put a test light on the plug wires and start tracing. Multimeter will work as well, I think a test light is less cumbersome and quicker.

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[Walker]

Your plug and adapter look pretty grungy. Clean them up and then test continuity in you adapter. Now test your truck for output at the plug.

[Pedernal]

Put a test light on the plug wires and start tracing. Multimeter will work as well, I think a test light is less cumbersome and quicker.

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This right here… check your truck fuses… most modern trucks have separate fuses for the wiring that goes to the trailer plug…. If you have power at the truck plug make sure the trailer is getting good ground as mentioned above.

[andre3k]

Also, match the functions not the wire colors. The colors might not necessarily be the same as the diagrams you see online. Have a helper in the truck to operate the lights, brakes and turn signals while you probe your wires with the test light. Clean out your connector with some contact cleaner if available and dab a bit of dielectric grease in there as well once its clean.



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[BrianL]

Clean your contacts on your truck. The corroded pin is your running lights

[RWB]

Bet it's a fuse in the truck. Hook up to a trailer with a short and it will pop.

[sqiggy]

Bet it's a fuse in the truck. Hook up to a trailer with a short and it will pop.

This was the first thing I did. Fuses are good

Put a test light on the plug wires and start tracing. Multimeter will work as well, I think a test light is less cumbersome and quicker.

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I don’t have a multimeter hence the “not a electrician guy”
But I think I have a test light somewhere.

Oh, ground on trailer is good.

[sqiggy]

Your plug and adapter look pretty grungy. Clean them up and then test continuity in you adapter. Now test your truck for output at the plug.

Yes they are. In fact, it was holding water and I had to use a small flat head screwdriver to clean out the mud. Think I have a can of contact cleaner around here somewhere.

[Pushbutton2]

The mistake I often make not having the key in the on position or the truck running.

Also is there's no body ground your test light won't work so hook the alligator clip of the test light to the ground in the plug of your testing the posts in the plug

[Jonathan]

Not sure what truck you have but on my F-250 there are two different fuse blocks. There is one in the cab and one under the hood, the trailer lights plug in was in the one under the hood. I had a similar problem with mine and spent way too much time before I looked in the manual.

[RWB]

What is the year and make on the truck. My F250 it's the funky square fuses.

[gatorgrizz27]

Had a problem with trailer brakes not working half the time on a 2003 Chevy we just bought. Cleaned the contacts, wiggled everything, couldn’t get it to work consistently. Swapped the plug out and it’s been fine 100%.

[Kingfisher789]

I would start with new hardware..... thats where your problem is.