How to Add 7-Way Wiring to Rear of Flagstaff 5th Wheel to Allow Towing Boat Trailer
Question:
I am wondering where to attach a 4 pin flat plug at the back of my Flagstaff 8528IKWS, I will occasionally be pulling a boat trailer and need to have it wired forrunning, brake, and signal lights. Some run them right from the front of the trailer but others say you can tie into existing wiring at the tail lights at the back of the trailer. I was hoping you could assist with this or provide a wiring diagram. Thanks.
asked by: Grant
Expert Reply:
The 4-pole format of trailer wiring includes only basic lighting signals for stop, tail and turn lights; in order to have trailer brake power you will need to convert the wiring to at least a 5-pole (one more circuit for brakes) or to the popular 7-way format which has circuits for brakes, reverse lights and auxiliary 12V power. An article on wiring is linked for you and this includes details about the circuits found on each type of wiring format.
If the taillight wiring in your Flagstaff 5th wheel is heavy enough to handle the extra power drawn by the lights on the boat trailer you wish to connect then you can tap into that wiring to get the basic lighting signals. I suggest checking with Forest River using the trailer's VIN. They can tell you if this is safe or if you need to run new wiring from the front of the trailer to the back.
The most secure way to add the new wiring is to install a junction box # 38656 on the front of the trailer which can serve as the connection point for both the existing wiring and the new 7-way wire # DW04914-1 you will run to the back of the trailer. You will need ring terminals like # 44-5310A. This can then connect to a 7-way socket like # HM48480.
Please note that tandem towing (towing two trailers at once) may not be permitted in all areas so you might want to check this ahead of your next trip.
Products Referenced in This Question
Ring Terminal - 12-10 Gauge Wire - 3/16" Ring ID
- Wiring
- Wire Connectors
- Ring Terminals
- 3/16 Inch Diameter
- 12-10 Gauge
- Flint Hill Goods
more information >
Hopkins Endurance 7-Way Trailer Connector Socket - Vehicle End - Ergonomic Design
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- Plug Only
- 7 Round - Blade
- Hopkins
more information >
Product Page this Question was Asked From
Deka Jacketed 4-Wire - 14 Gauge - Per Foot
- Wiring
- Wire
- Jacketed Wire
- 4 Wire
- 14 Gauge
- Deka
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Replacement 4.3" Monitor for Furrion Vision S Wireless RV Camera System
- Article: Trailer Wiring Diagrams
- Shop: Trailer Wiring Junction Box
- Shop: RV Camera
- Shop: Trailer Wiring
- Shop: Replacement Furrion Monitor Power Cable
- Shop: Adjustable Width Trailer Hitch Receiver for RVs, 22" to 72" Wide
- Shop: Curt Adjustable Trailer Hitch Receiver - 18"-51" Wide - 2" Drop - Class III - 2"
- Shop: Trailer Hitch
- Shop: Deka Wire - Jacketed 7-Wire - per Foot
- Shop: Furrion Vision S Wireless RV Backup Camera System w/ Night Vision - Rear Mount - 5" Screen
- Q&A: How To Pair Bluetooth Devices To The Furrion DV3300SBL RV Stereo System
- Q&A: How to Wire up a 5th Wheel Trailer so that a Utility Trailer Can be Towed Behind the Trailer
- Video: Trailer Hitch Installation - 2008 Jeep Grand Cherokee
- Shop: Brake Controller
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Q&A: How To Wire a 5th Wheel for Triple Towing a Trailer with Brakes
- Video: Curt Adjustable Width RV Trailer Hitch Installation - 2017 Forest River Rockwood Mini Lite Travel Tr
- Q&A: Installing a 4-Pole Trailer Connector at Rear of 5th Wheel for Towing Boat Trailer
- Video: Deka Wiring DW04914-1 Review
- Search Results: 7 pin connector cover
- Video: Curt RV and Camper Hitch - Frame Mount Hitch - C13701 Review
- Video: Lippert Underchassis Double Bin Storage Unit Review
- Shop: Fifth Wheel Hitch
- Search Results: adjustable width trailer hitch
- Search Results: wiring harness extension
- Search Results: under chassis storage
- Shop: Base Plate for Tow Bar
- Q&A: How to Measure RV Frame to Determine Fit of Curt Adjustable Width Trailer Hitch 13703
- Video: Review of Curt RV and Camper Hitch - Frame Mount Hitch - C13704