Wiring in a trailer plug...help? | Ford Explorer Forums - Serious Explorations

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Wiring in a trailer plug...help?


Active Member
October 31, 2010
Reaction score
City, State
Ridgecrest, Ca
Year, Model & Trim Level
92 xl
So today I needed to use a trailer and nobody seemed to be around to lend my a truck with a tow package so I ended up using my explorer bumper ball... However, I didn't have trailer light hook-ups and I couldn't wait the get the adapter to adapt to the wire harness under the bumper so I did things the hard way and it doesn't work... I went and got a 7blade truck side plug and cut the adapter plug off my explorer. Went through all the wires and labeled them according to their function using a light tester and wired them up to the plug and thought I was done. Plugged the trailer into it and nothing... No lights... Fiddled with it for hours moving wires around checking ground running individual ground wiring to the frame... and still nothing. I disconnected the wires from the plugs and connected the right brake light wire from the truck to the right brake light wire to the trailer and grounded the trailer directly to the frame of the explorer and still no lights. By this time my dad comes over and he is back with his truck which I ended up using and plugged the plug intot the truck and the lights work just fine... It just didn't make and sense why the lights were no working for the explorer worked every other truck... Especially when I was 100% supplying power to the lights on the trailer and was 100% grounded out directly to the frame of the truck...
Btw... It is a 92 explorer
The only thing I can think of is that the trailer lights have an individual grounding source but then how would the light tester work if i had it grounded to the frame of the truck...

This got me so stumped and fustrated today...

Any Ideas???

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Spend the $10 on a trailer light harness. Any auto store should have 1 for a 1st gen X.
Of get it off Ebay cheaper.

There are plenty of plug-in harnesses available for cheap, usually under $10. Most of these plug into the factory wiring behind the driver side cargo panel, and give you a 4-flat connector, which you can then adapt to whatever you need. You could also put the adapter plug back on your ride and get the correct plugs for making it into a 4-flat and then a 7-round adapter if that's what you need.

Trying to rig up the stock wiring with adapters doesn't seem to work too well. I had some luck getting a 5-flat to work with one specific boat trailer just hardwired into the factory wires, but it didn't work with anything else. Went to a plug-in 4-flat and it works with everything and all adapters that plug into it.

Plug-in adapters are the way to go, cutting into stuff just makes for problems and headaches.

Wow am i ever glad i found this forum since i did the same thing. I tried to hard wire it too and my boat trailer lights kinda work but the signals flash so fast you cant tell i am turning. So tomorrow i am going to an auto parts store to get the proper one. Thank you

You might have to order online, auto parts stores don't seem to carry the ones for the 91-94 Explorers these days, though some larger ones might or they can order them in.

Online is usually way less expensive as well.

So today i found a plug all by its self behind the bumper on kinda the middle of the bumper. It has 8 wires in theback of it. Is this the plug that my trailer harness lights will plug into? Thx for any more info

It's probably a harness for a trailer wire plug that goes on the bumper, but you'll probably need the other part to it, which is probably a Ford-only dealer item if it's even available anymore.

You could follow it back and see where it goes. If it goes to the wiring behind the jack compartment, it might just be a removable harness that you can replace with the aftermarket adapter that plugs in-between the stop/taillight wiring.

Okay its all done. Went to my autoparts store and they had one for a first gen X. It was a t plug i used and i hooked up my trailer and all the lights work as they should!! Finally, take the advice and time to get the proper plugs. It saved a lot of time and hassle oh and cursing too as i had nuthin but problems with the one i hard wired to the tail lights. Thanks sooo much!