Running Light Fuse Location on 2011 Ford F-150

Updated 06/20/2020 | Published 07/22/2018

Question:

My truck is a 2011 f-150 ecoboost. When the trailer lights are plugged in, the turn signal both work, and the brake lights as well. The running lights do not. I checked the running light receptacle on the the truck, and it indicates no power. Is there a fuse or relay on the truck that handles just the running lights, or is the outlet on the truck the problem? Thanks

asked by: Ron B

Helpful Expert Reply:

What you'll want to do is check inside the power distribution box in the engine compartment; there should be a relay located in the number 39 position. Also check the 15 amp mini fuse that should be in the number 43 position and the 20 amp cartridge fuse in the number 67 position.

If that does not fix the issue, there is some troubleshooting you can do. You will need to use a circuit tester such as # 40376 to test the connector on your F-150 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.

As I mentioned above, an important issue you will want to take a look at are the ground connections, as they can be the cause of numerous lighting problems. You'll want to make sure your grounds are securely attached to bare metal surfaces free of any paint, dirt or corrosion of any kind. Also check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged. I've added links to a pair of help articles on trailer wiring that you may also find useful.

expert reply by: Kyle S