Troubleshooting Trailer Wiring that Does not Function

Question

Question:

I have power to trailer light wires, but neither side is working blinkers or running lights.

asked by: Daniel H

0

Expert Reply:

It sounds like you have tested the circuits of the 4-way on your tow vehicle already, but if not you will want to use a circuit tester like our part # PTW2993 and test them individually like the video I attached demonstrates.

If there is voltage there at the connector at the correct times you know the problem lies in the trailer wiring. Most likely the problem is a bad ground or corrosion. I would start by inspecting the connector looking for corrosion and cleaning if necessary.

Next, I would recommend you inspect the grounds of the tail light assemblies. If the assemblies ground through the mounting hardware you will want to make sure the assemblies are installed onto a clean metal surface.

You should also inspect the condition of the wires from the connector all the way back to the light assemblies looking for any cut or exposed wire and fix as necessary.

I attached an FAQ on trailer wiring for you to check out also.

expert reply by: Jameson C

0

Answer 1

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 2

When wiring a trailer connector, it is best to wire by function, as wire colors can vary. We have an excellent wiring diagram on our website, I will provide you a link so you can look at it. If you are looking at the inside of the trailer connector…

view full answer...

Answer 3

Either way is correct. It depends on if you want to keep the semi-style 7-Way (if you need to tow that type of trailer) or if you will never be towing a semi-trailer. If you need to keep the 7-Way semi active on the truck, then you would need to make…

view full answer...

Answer 4

I have added a photo detailing the wiring connections for the Pollack Heavy-Duty, 7-Pole, Round Pin conncetor, #PK11700, see link. This is a SAE J560 compliant connector. The wiring diagram for the vehicle side connector, #PK11720, is pictured also.…

view full answer...

Answer 5

It's a wire color difference but not a function difference on the pins of the 7-way. The difference comes from the fact that the two different styles are representative of two different areas that uses trailers. Traditional is usually seen on…

view full answer...

Answer 6

Trailer wiring generally uses 16 gauge wire, part #16-1-1. However, with a long trailer like yours you may want to go with a larger like 14 gauge #DW07550-1 or even 12 gauge #12-1-1. Each size is sold by the foot. You will need to have the lights at…

view full answer...

Answer 7

On a 7 pin round which is the common connection on a semi trailer, the clearance/marker lights are at the 10 o clock position when you look at the trailer wiring connection. When looking at the connector on the back of the truck, that will put the…

view full answer...

Answer 8

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 9

You have it right so far, the 4-way connector is just as you have stated. Remember that Yellow has a L in it so that is the left side brake/turn signal and green has a R in it so that is the right side brake/turn signal. The colors for wiring a 7-way…

view full answer...

Answer 10

On a 7-Way connector the suggested minimum wire gauge for the White (ground) wire, the Red or Black (power) wire, and the Blue (brake power) wire is 12 gauge. The minimum wire gauge for the remaining Green (right turn/brake) wire, the Yellow (left…

view full answer...

Answer 11

On this page (typically below the product links) there is a helpful link section that will have the install instructions fo the Hopkins Breakaway kit part #20400 that you referenced. I also attached an install video that shows the kit installed as…

view full answer...

Answer 12

If your trailer has 7 wires running all the way back to the brakes, then yes, you can tap into the existing wiring. Each of your new brakes will have two wires for the brake magnet. One wire is for 12 volt power to the brake magnets and the other…

view full answer...

Troubleshooting Trailer Wiring that Does not Function

Products Referenced in This Question

Product Page this Question was Asked From

Featured Help Information

Miscellaneous Media

Continue Researching