Upgrading A 2005 Toyota Tundra With Factory 4-Flat To A 7-Way And Brake Controller

Updated 08/14/2026 | Published 08/10/2026

Products Featured in This Question

Redarc Tow-Pro Liberty Brake Controller w/ Custom Harness - Dash Knob - Up to 2 Axles - Proportional

(3105)

$200.00

Buyers Products Trailer Connector Adapter - 4-Way to 7-Way RV and 4-Way Flat

(201)

$20.70

Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires

(3536)

$118.67

Question:

Hey there. I have a 2005 Toyota Tundra with a factory 4-pin harness. Im looking for a brake controller and all needed parts to install it. I think I need the red82cr and337tc1474p. Is this all I would need to install it? Is there anything else I might need? Do I plug into the actual 4-pin and that basically converts it to a seven pin? Thanks!

asked by: Thomas M

Expert Reply:

Hi Thomas, nice truck!

The Redarc Tow-Pro Liberty Brake Controller w/ Custom Harness - Dash Knob - Up to 2 Axles - Proportional # RED82CR is definitely the right controller for your truck. Redarc currently makes the best brake controllers on the market and I'm sure you will be very happy with it!

For the wiring though, it will be slightly more work to get you what you need. Having the 44-Flat does make it a little easier and the Buyers Products 4-Way to 7-Way RV and 4-Way Flat # 337TC1474P will plug right into the 4-Flat, but more will be needed to get it working properly. All the other components can be pieced together though.

However, if I were doing this install, I would just get the Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires # ETBC7. This includes the Buyers 7-Way adapter, but it also has all the other wiring, butt/ring connectors, circuit breakers, and other hardware needed for the upgrade (see included image). It's an all in one kit and the better way to go. If you wanted to piece one together, just let me know and I can get you a parts list for what you will need (it's quite a few parts).

What kind of trailer are you going to be towing?