2005 Ford F150, Rear Park Lights Inop

This 2005 Ford F150 Pickup came in with the complaint that the rear park lights or tail lights were not working but the front ones were. I figured simple enough probably a blown fuse from towing a trailer with a short. Well I figured wrong. After checking thoroughly I found that the lights would flicker on and off if I wiggled the harness connector at the left rear of the truck.


Well I guess I need to see what’s going on inside this connector. I unplugged it and nothing obvious.

I located the brown wire and checked the drag resistance of the terminal and it was very loose.

In order to have room to work I had to drop the spare tire and release the fasteners that held the connector to the frame rail.

I also had to remove some more clips that were holding the harness itself to the frame rail.

With the harness connector now in a position that I could now work with it, I removed the internal locking cover with a small hook.

With the cover removed I could now access the individual terminal locks.

I released the lock and pulled the wire from the connector.

After thorough inspection of the terminal with a magnifying glass I determined that the terminal was okay except the obvious loose condition caused by a compressed spring tab.

Using a very sharp angled pick I was able to lift the inner spring tab and correct the loose condition. I worked slowly and went back and forth from side to side in order to bring the tension back evenly. I also slid a piece of thin wire in from the opposite end of the terminal to make sure there was a good lift to the terminal tab. If I had not been able to salvage the terminal, I would have two choices. Install a new terminal or bypass the circuit around the connector with a piece of wire and a couple of splice connectors.

After being sure the terminal would be okay, I installed the terminal back into the connector and added a touch of dielectric grease to help maintain the connection integrity. My observations lead me to believe that the mechanical resistance of the female terminal had been compromised by the lack of free movement between the mating terminals. Therefore when the terminals were forced to move from harsh bumps the terminals would dig in rather than slide. When they dig in the action works against the spring resistance and the spring tension is eventually compromised.

I double checked the male terminals for arcing and found no sign. Just to be sure I cleaned them slightly with a pencil eraser. By the way an eraser is the absolute best thing to clean a terminal with if you have enough access to it. You would be surprised at the some of the things I have gathered over the years to perform little trick repairs. Maybe one day I will do a post about some.

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