Sorry about the length of the post but here goes:
I found the plug as mentioned above and I was provided a link for a Hoppy T-connector. Right now the probblem I have is that I really need to know which wire from the flat 4 connector goes to which pin on the Hoppy adaptor (Hoppy P/N 40325) to be certain it is the correct plug.
I looked into this problem in a bit more detail today. I discovered that the plug I had located which the license place light wiring harness plugs into is in fact the trailer lighting plug as well. It is an 8 pin plug. The license plate wire harness that plugs into it only has two wires, a purple/white to provide power (12V) to the license plate lights lights and a black wire for the ground to the license plate lights. The other 6 pins on the license plate light wire harness plug are blank.
The upstream plug that the license plate wire harness plugs into has five wires going into it. The purple wire and black wire for the license plate lights, a yellow (LH turn signal/brake light), green (RH turn signal/brake light) and a brown/white (trailer running/parking lights). So clearly this plug must have been intended to serve as the connection for the trailer lights as well as the license plate lights. The only way to make this work would be with a T-type connector like the Hopy T-type connctor (Hoppy P/N - 40325).
Once I figured this out, I pulled the connector apart and used a multi-meter the check for power at the trailer light pins on the upstream connector. Nothing. Dead as a door nail. I only had power to the pin for the license plate lights and I had continuity at the pin for the ground.
Wondering why they would wire the vehicle with dead wires, I began looking for the fuse locations. I discovered that the 15A fuse for the trailer lights in the fuse box inside the vehicle on the driver's side of the dash was there and it was good. I then discovred that there is a big 30Amp fuse in the main engine compartment fuse/relay box and it was not there. Fortunately, the clips are there and one side had 12V. The owners manual says that this fuse is for the trailer parking lamps and the trailer turn signal lamps. I bought the proper fuse and installed it. Checked the plug again. Now I had 12V to the pin for the license plate lights and 12V to the pin for the trailer running lights but still no juice for either turn signal/brake light. At least I was making some progress.
Upon further investigation, I discovered that there is another relay box screwed in to the drivers side inner fender right next to the battery and it contains two relays for the trailer turn signal lamps. When I opened the box up, I discovered that these two relays were not there. Another trip to the parts store to buy the relays. Counter guy tries telling me that they don't make turn signal relays, only flashers. Fortunately I brought the owners manual with me to show him he was wrong. Turns out they did have the relays listed in their system and he had two in stock. Installed the relays and I now have power to all of the pins on the upstream plug. Big time progress!!! (or so I thought)
Now for the part where I am currently stuck. I can find T-Type connectors that will physically fit this plug. My problem has been finding a T-type connector where the wiring internal to the T-type plug connector matches what I have. For example, I found a T-type connector for a 93 - 99 Ranger (Hoppy Wiring Kit - P/N 40215) that physically fits but the pins on the Hoppy plug are wired opposite hand to what I have on my vehicle. For instance, if the upper left hand pin on mine is for the yellow (LH turn signal/brake), the T-Connector is wired so that this wire needs to be on the upper right hand pin of the upstream plug in order to provide power for this wire on the flat four connector. Hope that makes sense.
The only connector with a flat 4 connector that I could find for a 96 Explorer was a pig tail type that would plug diectly into the upstream plug and had a pig tail with a flat 4 connector on it. Problem with this is that it does not provide any means to reconnect my license plate light harness back in to the system. Also, I am almost certain that the wire arrangement to the individual pins on this connector is different than what is on my vehicle. I found a photo on another thread on this forum of the plug with the rubber boot from a 4-door Explorer that I believe this pig tail type connector is wired for and designed to plug into. The yellow, brown, green, and ground wires are all arranged differently than they are on my upstream plug.
I also found the trailer wiring kits that come with the converter boxes on them and require running a separate wire up to the battery to provide a constant 12V to the converter. These kits use a collection of T-conectors to tap into the various lights on my vehicle. This set-up would probably work but I really don't want to run the wire up to the battery and have a potentilal full time draw on the system and a poorly protected constant 12V wire that might cause some problems down the road. I suppose I could run the wire internally but it will be a minor P.I.T.A. that I would prefer to avoid particularly since it is pretty clear that Ford intended me to tap in off of that plug behind the drivers side brake/tail light lens. Unless my luck were to change, it is a pretty safe bet that I would bust one of the interiror panels in the process of running this wire internally.
My guess is that the Sport was wired differently than the 4-doors for some stupid reason. That said, Ford must have made a T-connector for this vehicle at some point but none can be found in their parts system now. I called both Hoppy and Drawtite to ask them about a T-connector. The Hoppy guy said that the only connector they had for a 96 Explorer was the one with the pig tail and that they did not have a T-type connector. Clearly this is not correct as the link you provided would indicate that they do (or at least did at one time) make a T-type connector for a 96 Explorer. I found one on Ebay with the part number you provided in the link and I bought it. It should be here some time next week.
If anyone has one of these T-conectors and can do a quick continuity test to determine which pin on the 8-pin plug corresponds to each of the four wires on the flat four connector, I would be eternally grateful. This would at least let me know that I have the correct one coming.
Also, if anyone has set up a 96 Explorer Sport or similar year for towing lights, I would be interested to hear how you did it.
Thanks for reading all of this.
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2003 F-250SD, 6.0 PSD
2008 Lincoln MKX
1996 Explorer Sport
1950 F1 (4 ea.)
1949 F2
1948 F6
1950 F6