Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The cost to diagnose the C2808 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The braking energy that is provided to the trailer is varied with a Pulse Width Modulated (PWM) signal along the circuit that switches between 0 volt and battery voltage, the higher the duty cycle the more braking power available. The Trailer Brake Control (TBC) Module varies the PWM signal based on various inputs such as the brake pressure transducer, TBC module manual slider switch and the TBC module gain buttons. With the vehicle stationary and with the manual slider switch fully to the left with a gain of 10, there should be greater than 10-12 volts supplied to pin 3 of the 7-pin trailer tow connector. Every 4 seconds the TBC module sends a voltage pulse along circuit CAT19 (BU) to pin 3 of the 7-pin trailer tow connector to determine whether or not a trailer is connected.
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