7-Way Trailer Connector and Brake Controller Installation on 1999 Ford F-350 Super Duty

Updated 02/26/2021 | Published 02/24/2021

Products Featured in This Question

Hopkins Endurance 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug

(75)

$85.84

Ford Replacement OEM Tow Package Wiring Harness, 7-Way (Super Duty)

(422)

$69.72

Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - Ford, Lincoln, Mercury

(1793)

$18.95

Adapter 4-Pole to 7-Pole and 4-Pole

(659)

$61.47

Tekonsha Primus IQ Trailer Brake Controller - Up to 3 Axles - Proportional

(2156)

$90.04

Question:

I have a 1999 F350 Superduty 7.3l, it has a 4 wire flat trailer plug. I need to know what I need As far as brake controller and trailer harness to be able to tow a 5th wheel camper? Thanks...

asked by: Archie C

Expert Reply:

For starters, you'll want to follow your existing 4 pole if it's the factory trailer connector. If it's plugged into a rectangular connector, you can use part # 118243 for a plug and play installation. The connector will be behind the rear bumper near the driver's side frame rail. Unplug the connector for the 4-pole and plug in the # 118243. Be careful not to damage the tabs on the connector.

If it's a round connector, you can use the # 37185 adapter. Plug the existing 4-pole into the 4 pole on the adapter. Ground the white wire on the adapter to the truck frame, and connect the blue and black wires as follows. Find the round connector on the frame rail, and locate the harness that feeds it. Pull back the wire loom and/or tape covering the wiring harness and locate the orange and the blue wire. Cut both wires. Attach the blue wire from the harness to the blue wire from the adapter, and attach the orange wire from the harness to the black wire from the adapter.

At this point, if you're using the # 118243 you'll install the relays and fuses included with the kit. Use the owner's manual or the listing on the fuse box lid to locate the following fuse and relay locations:

• Trailer Tow Electric Brake Fuse
• Trailer Tow Battery Charge Fuse
• Trailer Tow Electric Brake Relay
• Trailer Tow Battery Charge Relay

The # 118243 includes the fuses and relays, if you're installing the 7-way using the # 37185 adapter, you'll need to obtain those from either an auto parts store or from Ford.

For a brake controller, I'd recommend the Tekonsha Primus, part # TK90160. The Primus is an inexpensive proportional brake controller, which is what you'll want for the most predictable and safe braking. You'll also need the # 3035-P brake controller harness, that plugs in under the dash as shown in the linked video.

The video shows a different controller being installed, but the procedure for the controller I recommended would be the same as what's shown.