12v for trailer
New User
Joined: Jun 2002
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12v for trailer
I have a '94 F150 5.8L. I have the kit to plug into the wiring harness (4 to 7) at the rear of the truck and the trailer lites work fine. I need 12V for the trailer. I believe the truck has the tow package. There is a relay and fuses in the PCM. Is there another connector I've missed. Any and all suggestions welcome.
Posting Guru
Joined: May 2002
Posts: 1,673
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From: Chicago Area
12v for trailer
[updated:LAST EDITED ON 18-Jun-02 AT 12:15 PM (EST)]Not sure I'm understanding you. The 4 wire plug only has ground, tail, bright right, and bright left. The 7 wire has a constant +12v (when ignition is on), but that might require the pigtail in the dash (for electric trailer brake controller) to be properly connected. If you are adapting from the 7 wire plug on your truck to a 4 wire plug on your trailer, one of the connections you lose is the constant +12v.
MrBSS
MrBSS
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Joined: Aug 2001
Posts: 67
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12v for trailer
Roscot-
I am dealing with the same issue (I think) on my 99 Expedition. While I do not have the towing package, my wiring harness does support a 7-wire plug. I also have the relays needed to get the power to the back of my truck. Essentially, my current 4-wire trailer connector is a 2-foot pigtail that plugs into the wiring harness. I checked out the pins in the harness connector, and I do have active wires for the electric brake control and the constant power. However, my current 4-wire pigtail does not hook up to the pins in the harness.
I have checked out the Hoppy wiring kits at the auto parts stores, but my particular vehicle does not warrant a plug and play 7-wire connector. Ford does make one, but they want around $100 bucks for it. Basically, the non-trailer tow package has the 4-wire pigtail, anbd the trailer tow package equipped vehicles come with the 7-wire pigtail. The vehicle wiring harnesses are the same for both versions.
I don't want to splice into the vehicle harness, and I don't want to blow a hundred bucks, so I plan on buying a diferent aftermarket wiring kit and making the necessary modifications. Hoppy does make a t-connector that will fit my plug, and I will cut off the end and rewire the pigtail to get the right wires to the 7-wire connector. Not the best option, but I have no other solution. I would recommend a visit to autozone or Carquest - they may make an adapter for your truck that costs under $30.
Jerm
I am dealing with the same issue (I think) on my 99 Expedition. While I do not have the towing package, my wiring harness does support a 7-wire plug. I also have the relays needed to get the power to the back of my truck. Essentially, my current 4-wire trailer connector is a 2-foot pigtail that plugs into the wiring harness. I checked out the pins in the harness connector, and I do have active wires for the electric brake control and the constant power. However, my current 4-wire pigtail does not hook up to the pins in the harness.
I have checked out the Hoppy wiring kits at the auto parts stores, but my particular vehicle does not warrant a plug and play 7-wire connector. Ford does make one, but they want around $100 bucks for it. Basically, the non-trailer tow package has the 4-wire pigtail, anbd the trailer tow package equipped vehicles come with the 7-wire pigtail. The vehicle wiring harnesses are the same for both versions.
I don't want to splice into the vehicle harness, and I don't want to blow a hundred bucks, so I plan on buying a diferent aftermarket wiring kit and making the necessary modifications. Hoppy does make a t-connector that will fit my plug, and I will cut off the end and rewire the pigtail to get the right wires to the 7-wire connector. Not the best option, but I have no other solution. I would recommend a visit to autozone or Carquest - they may make an adapter for your truck that costs under $30.
Jerm
