2025 4Runner Trailer Backup Guide & Brake Controller

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2025 is the first model year Toyota has ever offered a factory-integrated trailer brake controller on a 4Runner! Previously, 4Runner owners had to install aftermarket brake controllers like the one from Red Arc (https://www.redarcelectronics.com/us/toyota/4runner) to tow safely with electric trailer brakes. The addition of a built-in, gain-adjustable brake controller in 2025 brings the 4Runner is a big deal for anyone towing off-road trailers, campers, or utility loads.

Setup, Calibration, and Operation
(Reference: 2025 Owner’s Manual, pg. 437–444)
Link to Owners Manual: https://trail4runner.com/wp-content/uploads/2025/03/2025-4runner-owners-manual.pdf

The 2025 4Runner offers a built-in Trailer Backup Guide and a Toyota Genuine Trailer Brake Controller to help make towing safer and easier. Here's how to get started with both systems

Trailer Brake Controller Overview​

The trailer brake controller manages trailer braking through the 7-pin wiring harness and includes a manual brake slider and gain adjustment.
It works with most electric and electric-over-hydraulic trailer brakes (up to 3 axles), but not with hydraulic surge brakes.

Key Features:

• Gain range: 0.0 to 10.0 (adjusted in 0.5 increments)
• Gain settings control how strongly the trailer brakes are applied
• Manual brake slider engages only the trailer brakes for checking or control
• Brake output is displayed on the multi-information display

To set the gain:

1. Start with gain at 5.0
2. Drive 20–25 mph on level ground
3. Use the manual slider to apply brakes
4. Increase or decrease gain until trailer wheels are just below lock-up
5. Recheck after load or road conditions change

Trailer Backup Guide Overview​

Trailer Backup Guide helps you reverse with a trailer using either.

• Guidance Mode: Displays a trailer path based on steering angle
• Straight Path Assist: Automatically controls steering to keep the trailer backing in a straight line

Activation Steps:

1. Add trailer via "Trailer Settings" in the multi-information display
2. Press the Trailer Backup Guide switch to turn the system ON
3. Complete initial trailer calibration by following on-screen instructions
4. Shift into Reverse to enable Guidance Mode
5. Tap the multimedia screen to activate Straight Path Assist

The system uses the rear camera and trailer hitch light for nighttime visibility. Calibration is based on trailer length (6.6–26.2 ft) and ball mount length (4.5–18.5 in).

Operation Tips & Limitations​

• Keep the rear camera clean and unobstructed
• Avoid sharp trailer tongue changes post-calibration without re-calibrating
• The system disables above ~5 mph or if the camera loses trailer tracking
• Straight Path Assist can be overridden with steering input
• Always monitor your surroundings; the system does not handle braking

Safety Warnings​

• Only use with compatible trailer types and within operating limits
• Check trailer brake condition before towing
• Never rely solely on automated guidance—driver remains responsible for control
• Keep the hitch light and rear camera properly aligned for optimal performance

2025 4Runner Trailer Backup Guide and Brake Controller Diagram​

Refer to the Owner’s Manual (pages 437–444) for switch layout, calibration visuals, and gain setting instructions.