4 Pin Flat Connector - Question On Trailer/Marker Light Wire

[david.bell.9678]

Hello.


I did a Forum search and could not find info so I put in Electrical rather than Towing.


2012 Ford Expedition XLT. It has a standard 4 pin flat connector that is OEM.


Two weeks ago I could not get the trailer rear and marker lights to work. The left and right turn signal both worked, just no marker lights. In checking the 4 pin flat mounted on the Expy I noticed the little metal sleeve inside the connector for the TM pin had been pulled out. The right and left turn signal still worked.


I could not find a sleeve to fit in the connector so I purchased a new 4 pin flat and cut off the OEM connector. I have everything wired up correctly. I get left and right turn signals on the trailer but no trailer rear and marker lights.


Since all of the Expy’s lights work properly it appears to not be a fuse related to the vehicle. Does anyone know if there is a separate fuse that is for the 4 pin wiring harness? The wires have never been messed with and are in their original wiring loom so I don’t think the single TM wire being nicked or severed is the issue.


Any ideas on where to go from here?


Thanks,

Dave

 

[Flexpedition]

Check the fuse section your owners manual. There is an underhood power box and inside of it you do have a fuse specifically for trailer running (parking) lights. If its blown, you won't have trailer running lights but the vehicles lights will work just fine, and the trailers left/right turn and brake lights will work just fine. My guess is that fuse is blown.

 

[david.bell.9678]

Thanks for the thought. I looked for this fuse in the manual before but must have read over it. I will study the manual again and see what fuse it is.

Dave.

 

[Bedrck47]

Dave as mentioned above Check fuse #28 There also is a relay for the running lamps
Trailer tow relay Parking Lamps
Make sure it is installed Again check the owners manual

 

[Bedrck47]

See the attached print It is for the 2010 Model Year but your 2012 should be the same

Also the turn signals have their own fuse and relay Keep that in mind if you ever have a problem with the tow connection and the expy's lights work but the tow connection doesn't

 

[Bedrck47]

You will be concerned with page 3

 

[david.bell.9678]

Fuse #28 was the culprit. As my luck goes the store stocked up to 20 amp so i had to go elsewhere to get a 25 amp.

As an aside to this issue, if someone had to live life over again, it would be good to come back as the original fuse guy or gal. They could decide to simplify the world and people for centuries to follow would sing their praises. Probably could make a few bucks along the way.

Thanks for the help on this forum.

 

[Bedrck47]

Make sure you carry extra fuses Those fuses for the trailer connector circuit are prone to blow more so that the rest of the fuse They are prone to water and corrosion and the trailer lights can also have problems with water and corrosion. Get some dielectric grease and put some on the trailer connector contact area