2008 Taco. Was renting a U-Haul trailer this morning. Lights to the trailer did not work. went through all the fuses, and they were fine. Tested the connection at the hitch, and was getting no energy. i'm assuming I have a ground somewhere? I'm not the smartest at this kind of stuff.

Were the parking lights on with the ball completely seated when you tested the lights?

Stat Monitor Repairman said:

---

Were the parking lights on with the ball completely seated when you tested the lights?

---

Yes.

Tested the connection... with a volt meter on the terminals?

Is everything behind the bumper plugged in tight?

Took it to the mechanic. They said everything tested fine.

Connected the new trailer. Nothing.

Maybe clean the connections? I'm stumped.

You didn't throw a coat of paint on a rusty trailer ball did you? (speaking from experience)

Nope.

Ground.

Trailer light problems are 90% ground.

There should be a ground wire through your pickup. Follow the wire from the trailer plug upstream until you find a wire bolted to the frame. Clean and retighten that connection.

From the trailer plug, follow it to where that ground wire bolts to the trailer frame. Clean and tighten that one.

CanyonAg77 said:

---

Ground.

Trailer light problems are 90% ground.

There should be a ground wire through your pickup. Follow the wire from the trailer plug upstream until you find a wire bolted to the frame. Clean and retighten that connection.

From the trailer plug, follow it to where that ground wire bolts to the trailer frame. Clean and tighten that one.

---

Ok, I will do that. Thanks!

Try a connecting a different U-Haul trailer & see if the lights work.......could be the trailer has an issue.

will.mcg said:

---

Try a connecting a different U-Haul trailer & see if the lights work.......could be the trailer has an issue.

---

Well, dude "tested" the receiver on my truck, and said it didn't work. My mechanic said there was no issue.

But, yeah, I'll try a different trailer next time.

Every problem I have ever had with trailer wiring was either a bad ground (salt corroded wire, corroded bolt on light connection, etc.) or a burnt out bulb in the light assembly.

Well, running lights work. Didn't check that earlier. Indicates a ground issue. Going to get a tester for my truck connection just to rule that out. Then, I'll go around the trailer, or just do a complete re-wire.

Tested the truck receiver - everything checks out. No issues.

Just going to re-wire the trailer to make sure it gets done correctly.

When re-wiring trailers in the past, I've usually used a 4 pin set up, and then used an adapter to my truck.

The current trailer has a 7-pin setup which I would prefer. I'm not familiar with how to wire those. I usually haven't seen those available to purchase. Can you purchase those kits?

You can get the kits from etrailer. They wire the same as your 4 pin except they have a extra pins for backup lights, brakes, and aux power.

lb3 said:

---

You can get the kits from etrailer. They wire the same as your 4 pin except they have a extra pins for backup lights, brakes, and aux power.

---

I didn't see (or haven't found) a full 7 pin replacement wiring system for a trailer with lights. All of the replacement wiring systems with lights are 4 pin. I'd really rather not have to use the 4 pin to 7 pin adapter to plug in my truck, though I'm not familiar with 7 pin replacement wiring.

Basically, I want something like the 4 pin replacement sets with a seven pin connector.

????

https://www.etrailer.com/Wiring/etrailer/e99010.html

or

https://www.etrailer.com/Wiring/etrailer/e99011.html

???

I'm a little confused, didn't you say it was a UHaul trailer? Are you wiring it, or trying to wire your pickup?

CanyonAg77 said:

---

????

https://www.etrailer.com/Wiring/etrailer/e99010.html

or

https://www.etrailer.com/Wiring/etrailer/e99011.html

???

I'm a little confused, didn't you say it was a UHaul trailer? Are you wiring it, or trying to wire your pickup?

---

The original problem was with a Uhaul trailer. The guy "tested" my truck wiring, and said the trailer connector wasn't getting power (I know that is false, as I have tested it and my mechanic tested it).

I'm completely dumb 7 pin systems. I saw those 7 pin wiring harnesses, but didn't see any lights that came with them. The 4 pin harnesses usually come with lights, so that is where the confusion came from. I do know I can simply purchase the lights, or use the ones already on the trailer.

Basically, I'm going to check the wiring on my existing 6x10 trailer with a multimeter - found a video on how to do it (right now, the running lights work, but the turn signals and break lights don't work - so seems like a short) to see if there are any ground issues. I already tested my truck with a tester (all checked out), which I bought at Autozone.

I've always re-wired with 4 pin connectors, and am completely stupid on 7 pin connectors (I know the extra 3 wires are for brake control, etc., but have never looked at them on a trailer - I learn by doing, not by watching a video or reading something).

https://www.etrailer.com/faq-wiring.aspx

You can buy a 7-pin connector, take your normal four wires from the trailer, wire those in, ignore the other three.

And sorry, I don't know how to show you by doing, over the Internet. Scroll through the link above, there are some pretty good explanations and illustrations.

CanyonAg77 said:

---

https://www.etrailer.com/faq-wiring.aspx

You can buy a 7-pin connector, take your normal four wires from the trailer, wire those in, ignore the other three.

And sorry, I don't know how to show you by doing, over the Internet. Scroll through the link above, there are some pretty good explanations and illustrations.

---

Ok, that is what I thought - to ignore the other 3 wires. I know how to do the rest. Thanks.

Issue was not a ground. It was that the ball of my truck was not greased enough. Problem solved.

zooguy96 said:

---

Issue was not a ground. It was that the ball of my truck was not greased enough. Problem solved.

---

Well that was part of the whole ground system...

I meant a wiring ground. Thx.

zooguy96 said:

---

I meant a wiring ground. Thx.

---

I know...just being a smartass.

txags92 said:

---

zooguy96 said:

---

I meant a wiring ground. Thx.

---

I know...just being a smartass.

---

Well, better to be a smartass rather than a dumbass.

zooguy96 said:

---

Issue was not a ground. It was that the ball of my truck was not greased enough. Problem solved.

---

Uhhhhhh....unless there's a joke I'm missing, the ground is the problem.

As mentioned, meant a wiring ground.

Thanks