Troubleshooting No Running Lights When Hooked Up to U-Haul Trailer

Question

Question:

Uhual trailer I have a uhual hitch installed, the break lights and turning signals work but I was unable to rent the trailer due to the lights that turn on, on the side of the trailer for night time driving.

asked by: Felix P

0

Expert Reply:

If the running lights on the U-Haul trailer were not working when hooked up to your vehicle, then I first recommend testing the 4-Way or 7-Way (whichever you have) and testing the pins with a circuit tester like # PTW2993. Have somebody run through the lighting functions on the vehicle while you test the pins. If you don't get any power to any of the pins with the running lights activated, then you at least know the issue is somewhere on the vehicle and not on the trailer you hooked up to.

Inspect the connector itself for any debris or corrosion that needs to be cleaned out. Take a look at the wiring at the back of the connector for any exposed or pinched areas that need to be replaced. Also make sure the main harness ground is securely attached to a clean bare metal surface.

If everything looks good, I recommend checking your vehicle's owner's manual for the fuse locations to see if there is one for trailer running lights. If so, make sure this fuse is present and in good condition.

If you are still having issues, please let me know and we can continue to troubleshoot. I have also attached a trailer wiring troubleshooting article that you might find helpful.

expert reply by: Chris R

0

Joe

8/19/2025

I try all the fuses The daylight still don't work when I connect the trailer

Chris R.

8/20/2025

@Joe Hey Joe, I'd probably check the connector itself next (unless it's brand new) to see if there is any debris or corrosion built up that might be causing a short, brushing out as needed. Also, this is going to sound dumb...but make sure too that you actually have the running lights on in the vehicle. Let me know what you find.

Answer 1

Hello Ben, Glad you got the new hardware for swapping over your hitch, as you should never re-use the hardware since it stretches over time. As you’ve noticed, the frame didn’t change between the 2018 and 2022 Chrysler Pacifica, but the wiring did.…

view full answer...

Answer 2

It could be a tow package fuse on the vehicle. Use the owners manual to find the locations of fuses/relays related to the tow package wiring to check them and replace as needed. If the issue is not a fuse or relay then you can test the vehicle side…

view full answer...

Answer 3

First thing to check is for corrosion on the pins of your trailer wiring connector. Make sure the trailer's 4-way is clean and free of corrosion. Sandpaper fixes this pretty easy. Next try unplugging and plugging in the trailer wiring harness…

view full answer...

Answer 4

Start off by making sure you connected the tail/running lights to the appropriate pin on your trailer's 4-Way or 7-Way depending on what kind of connector you have. For a 4-Way the pin should be the brown colored wire. This will also be the pin…

view full answer...

Answer 5

Hey Charles, thanks for reaching out. I will have to STRONGLY discourage you from using an alternate power source for the converter module on your daughters 2021 Pacifica. I know getting the wire to the battery can be a pain, and we actually get this…

view full answer...

Answer 6

There is a possibility that your trailer light converter has gone bad. Testing it is pretty easy. What you will want to do is test the wires going into the box of the converter box for voltage with a circuit tester like the #PTW2993 to see if there…

view full answer...

Answer 7

I am assuming you are referring to the Peterson Square Trailer Tail Light part #432400. If this is the case, on the back of the taillight assembly, there are 4 wire holes for each function located at the top of the tail light assembly. The top two…

view full answer...

Answer 8

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

view full answer...

Answer 9

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

view full answer...

Answer 10

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

view full answer...

Answer 11

According to Blue Ox, it'll take an experienced installer about 4 to 5 hours to complete the installation of their #BX1128 Base Plate Kit on a 2016 Jeep Grand Cherokee. The install isn't what I'd call super-difficult, but the installation…

view full answer...

Answer 12

The OEM prep package consists of 4 "pucks" in the bed of the truck that will allow you to drop in puck style hitches for easy installation and removal, that gives you a completely clear bed when not in use. The B&W Companion OEM 5th…

view full answer...

Troubleshooting No Running Lights When Hooked Up to U-Haul Trailer

Products Featured in This Question

Featured Help Information

Miscellaneous Media

Continue Researching