Troubleshooting Wiring Harness on 2015 Ford Explorer

Updated 06/02/2020 | Published 05/29/2020

Products Featured in This Question

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(490)

$37.13

Dielectric Grease for Electrical Connectors, 2 oz.

(1459)

$10.96

4-Pole Trailer End Connector

(38)

$8.25

Cordless Circuit Tester

(14)

$19.25

Question:

Hi there, I just installed my t harness onto a 2015 ford explore that didnt have the two connections already connected as most people do but I had the female connector so I connected to that as I’ve read some other people did and I don’t have power to my trailer lights. What can I check to make sure Where there isn’t any power.

asked by: Ashley T

Expert Reply:

I wasn't able to find your order number so I'm not sure what harness you purchased from us specifically for your 2015 Ford Explorer, but if it was the T-One Vehicle Wiring Harness # 118540, and you didn't have the two connectors, you would only need to plug it in to the connector shown in the accompanying photo I added. This is from the linked video install of this harness on a 2015 Explorer. If you did this and the connectors matched up but you still don't have power there are a number of troubleshooting steps you need to take.

The first thing to do is take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit Tester # PTW2979 would be my strong recommendation due to how easy it is to use - and test the connector on your vehicle after disconnecting it from your trailer. Check the wiring going into your harness from your tail lights to see if those wires are carrying the correct signals, if not then the issue is with the vehicle wiring.

If the signals going to your harness are okay, you'll need to test the signals coming out of the harness, and if they are correct then your issue is likely going to be with the trailer side wiring. You will also want to check your trailer connector for corrosion, which can be green or white in color. A build-up of corrosion can interfere with the signals getting through the connectors so if it is present you are going to need to replace your trailer wiring harness with 4-Pole Trailer End Connector # 18004. You'll also need to make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion.

I have added links to a pair of help articles on trailer wiring, including a troubleshooting guide which I highly recommend taking a look at.

Additionally, I also highly recommend using Dielectric Grease for Electrical Connectors # 11755 to help prevent any type of corrosion in your connector; using it will increase your 4-way's durability and extend its lifespan.