Installing 7-Way Connector on 2004 Ford Expedition with 4-Pole Trailer Connector
Products Featured in This Question
Question:
2004 Ford Expedition 5.4L with factory 4-pin connector. There is a blue wire taped up within the rear wiring. Can I safely assume that this wire is connected to the factory plug under the dash? If so, I assume that I would only need your 4-pin to 7-pin adapter, the brake controller with this pigtail, and then run a 12V auxillary wire from the battery? I hope this is correct. I am planning to tow a camper trailer and would need the 12V auxillary to charge a battery on the camper. Am I missing anything?
asked by: BRYAN P
Expert Reply:
You are correct. That blue wire carries the output from the brake controller. To convert your 4-pole to a 7-way, use an adapter like part # 37185. The connector on the adapter would connect to your existing 4-pole. The remaining wires would connect as follows; the white wire would ground to the vehicle, the blue wire connects to the blue brake controller output wire and the black wire would be extended to attach to the positive battery terminal using an inline 40 amp circuit breaker like part # 9510. The purple wire is typically connected to the reverse light circuit. If your trailer does not have reverse lights, this wire can capped off and bundled up out of the way.
The 12-volt feed off of the trailer connector can be used to maintain your battery, but be sure to unplug the trailer when the vehicle is not running so that the tow vehicle battery does not discharge. We also offer a battery isolator part # PK5231201 that would prevent the battery from running down by cutting the power to the 12-volt trailer accessory feed when the ignition is switched off. Keep in mind that this circuit won't have enough power to charge a dead battery, but it will keep a battery maintained. When shore power is available, you could use a battery charger like the CTEK # CTEK56353 to recharge the battery.

Product Page this Question was Asked From
40 Amp In-Line Circuit Breaker - Perpendicular Mount Bracket
- Accessories and Parts
- Wiring
- Circuit Breaker
- 40 Amp
- Pollak
more information >
Continue Researching
- Shop: Adapter 4-Pole to 7-Pole and 4-Pole
- Shop: Brake Controller
- Shop: Tekonsha Prodigy P3 Trailer Brake Controller w/ Custom Harness - Up to 4 Axles - Proportional
- Search Results: tekonsha 3035~p
- Video: Setting up the Adapter 4-Pole to 7-Pole and 4-Pole on your 2018 Chevrolet Express Van
- Shop: 40 Amp In-Line Circuit Breaker - Perpendicular Mount Bracket
- Search Results: tk23hr
- Search Results: 37185
- Video: Installing the Adapter 4-Pole to 7-Pole and 4-Pole on your 2011 Ford Explorer
- Video: How to Set Up Your Adapter 4-Pole to 7-Pole and 4-Pole on a 2011 Ford F-150
- Video: In-Depth Review of the Adapter 4-Pole to 7-Pole and 4-Pole
- Shop: Trailer Wiring
- Shop: Demco Channel Tongue Trailer Coupler - Zinc - 2-5/16" Ball - 3" Channel - Bolt On - 18K
- Shop: Demco Channel Tongue Trailer Coupler - eZ-Latch - Silver - 2" Ball - Bolt On - 10,000 lbs
- Shop: Demco Channel Tongue Trailer Coupler - eZ-Latch - Silver - 2" Ball - Bolt On - 10,000 lbs
- Shop: Demco Straight Tongue Trailer Coupler - eZ-Latch - Zinc - 2" Ball - Bolt On - 10,000 lbs
- Shop: Trailer Hitch
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Search Results: trailer wiring
- Video: Finding the Right Trailer Wiring Harness
- Search Results: trailer hitch
- Article: Trailer Wiring Diagrams
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: trailer brake controller
- Q&A: Wiring and Brake Controller Needed for 1996 Ford F-150 with 4-Way Flat
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Search Results: brake controller
- Video: Feature Breakdown: Universal Installation Kit for Trailer Brake Controller
- Article: Brake Controller Installation: Starting from Scratch