curt DISCOVERY 51126 - User Manual

The CURT Discovery™ Next Brake Controller (model 51126) is an electronic device designed to manage trailer brakes, ensuring smooth and firm stops. It is suitable for use with 12-volt negative ground systems.

Function Description:

The brake controller activates trailer brakes proportionally to the pressure applied to the manual control or vehicle brake pedal. It allows for adjustments to both "gain" (maximum power to trailer brakes) and "load sensitivity" (trailer brake aggressiveness) to suit individual driver preferences, trailer load changes, and varying road conditions. The device features an LED display that shows output settings, operational modes, and indicator sequences, aiding in setup, monitoring, and troubleshooting.

Important Technical Specifications:

Power System: 12-volt negative ground systems only.
Wiring: Requires a minimum of 10-gauge stranded wire for positive (with 30-amp circuit breaker) and ground connections directly to the tow vehicle's battery. A 10-gauge blue wire connects from the tow vehicle's trailer plug 'BRAKE' terminal to the brake control.
Circuit Breaker: 30-amp, auto-reset circuit breaker.
Output Scale: Manual control output is shown on a scale from 1 to 9.9.
Load Sensitivity Scale: 1 to 9 scale.
Mounting: Can be mounted securely to a solid surface, with the angle not affecting operation or calibration.
Compatibility: Can be used with CURT custom vehicle harnesses, CURT universal splice-in pigtail harnesses (#51515 / #51516), or the CURT universal brake control wiring kit #51500.

Usage Features:

Controls:
- Display: LED screen showing current settings and indicators.
- Load Adjustment (#2): Black rocker switch to the left of the display, adjusts trailer brake aggressiveness (1-9 scale).
- Gain Adjustment (#3): Orange rocker switch to the left of the controller, establishes maximum power to trailer brakes (increases/decreases power level).
- Manual Override (#4): Pinch trigger on the right side of the display, applies trailer brakes for slow speed reduction, showing output from 1 to 9.9.
Modes:
- Manual (M 0.5): Indicates manual override output is active.
- Auto (A 2.3): Shows output at the brake pedal, displaying power from 0.5 to 9.9 when vehicle brakes are applied.
- Gain (G 4.5): Shows current gain setting and allows adjustment.
- Load Sensitivity (L 5): Shows current load sensitivity setting and allows adjustment.
- Brightness (3): Adjusts screen brightness.
- Day Mode / Night Mode: Allows switching between display brightness settings for different lighting conditions.
Indicators:
- CURT (Calibration): Appears during start-up or restart.
- OVERLOAD (Overloaded): Indicates a brake controller overload or short-circuit condition in the trailer brake wire.
- LOW VOLT (Low Voltage): Indicates a low battery voltage condition, meaning the controller is not receiving enough voltage.
- SHORT (Electrical Short): Indicates a stop lamp overload or short-circuit condition, or if the stop lamp wire is grounded to the trailer or the bulb is burnt out.
- DISCONNECTED (Disconnected): Flashes when the trailer is disconnected or if brakes are pressed with no trailer connected.
- CONNECTED (Connected): Indicates a trailer has been successfully connected.
- NOT CONNECTED (Not Connected): Appears when brakes are applied, and no trailer is connected.
- RESET CONNECTION (Reconnect): Indicates the trailer needs to be disconnected and reconnected.
Initial Setup: Involves connecting the trailer, allowing the controller to sense it, and then making preliminary gain and load adjustments with the engine running. The controller retains the last settings upon restarting.
Test Drive & Adjustment: Requires driving on a dry, level surface at approximately 25 mph. Adjust gain to achieve firm stops just short of trailer tire lock-up. Then adjust load sensitivity for smooth, firm stops. This process should be repeated for changes in weather, weight, or loading.

Maintenance Features:

Troubleshooting Guide: The manual provides comprehensive troubleshooting steps for various display indicators and conditions, both with and without a trailer connected.
Bench Test: Instructions are provided for a bench test using a standard automotive bulb and a 12V battery to verify proper wiring and controller functionality before full installation. This helps identify issues like incorrect wiring or a non-operational controller.
Wiring Diagram: A detailed wiring diagram is included to assist with correct installation and troubleshooting of electrical connections.
Warranty & Product Registration: CURT offers product warranties, and users can register their purchase or provide feedback via curtmfg.com/registration.