Using 4-Pole to 7-Way Adapter Like # 37185 on 2008 Ford F150

Question:

2008 xlt Ford fwd. I purchased 4 and 7 trailer plug and ebrake control and installed it. It works fine but the video didnt show what 12 volt wire to splice into at rear of truck. Purple went to e brake control and black went ?. I spliced it to the wire that was next to purple wire for e brake control. Now when it is plugged into the travel trailer truck wont start and if I unplug it it starts but when I plug it in when it is running i cant shut it off.

asked by: Ted

Expert Reply:

It sounds as if something has been wired incorrectly.

If you are using a 4 pole to 7-way adapter like part # 37185, it would wire as follows:

The 4-pole portion would connect to the existing 4pole trailer connector.

The white wire grounds to clean metal on the vehicle frame.

The blue wire carries the output voltage from the brake controller, and would connect to a blue wire ran from the truck cab. This wire can be found along the drivers side frame rail. You might have to remove the wire loom or electrical tape from the wiring harness and trace it back toward the front of the truck to locate the wire.

The black wire on the adapter is for the 12-volt accessory feed. The black wire would attach to an orange or red wire which is also located in the wiring harness located along the frame rail.

The purple wire from the adapter is typically used for reverse lights on the trailer. If your trailer is so equipped, this wire would tap into the reverse light circuit on the truck. If not needed, this wire can be capped off.