If power assist is lost for any reason (for example, repeated brake applications with the engine off), the brakes will still function. However, you will experience a substantial increase in braking effort to stop the vehicle.
If either the front or rear hydraulic system loses normal braking capability, the remaining system will still function with some loss of overall braking effectiveness. This will be evident by increased pedal travel during application, greater pedal force required to slow or stop, and activation of the "Brake Warning Light" and the "ABS Warning Light" (if equipped) during brake use.
Four-Wheel Anti-Lock Brake System
WARNING! The Four-Wheel Anti-Lock Brake System contains sophisticated electronic equipment. It may be susceptible to interference caused by improperly installed or high output radio transmitting equipment.
This interference can cause possible loss of anti-lock braking capability. Installation of such equipment should be performed by qualified professionals.
The Four-Wheel Anti-Lock Brake System (ABS) is designed to aid the driver in maintaining vehicle control under adverse braking conditions. The system operates with a separate computer to modulate hydraulic pressure to prevent wheel lockup and help avoid skidding on slippery surfaces.
The system's pump motor runs during an ABS stop to provide regulated hydraulic pressure. The pump motor makes a low humming noise during operation. This is normal.
The ABS conducts a low-speed selftest at about 10 mph (16 km/h). If you have your foot lightly on the brake while this test is occurring, you may feel slight pedal movement. The movement can be more apparent on ice and snow. This is normal.
When you are in a severe braking condition involving use of the ABS, you will experience some pedal drop as the vehicle comes to a complete stop. This is the result of the system reverting to the base brake system and is normal.
Engagement of the ABS may be accompanied by a pulsing sensation. You may also hear a clicking noise.
These occurrences are normal, and indicate that the system is functioning.
ABS Warning Light
The ABS includes an amber warning light. When the light is illuminated, the ABS is not functioning. The system reverts to standard, non-anti-lock brakes.
WARNING!
Hydraulic Brake Assist - 2500/3500 Models Only (Except Power Wagon)
The brake system power assist is provided by a hydro-boost unit which shares fluid with the power steering system. You may experience some clicking or hissing noises from the hydro-boost system during hard braking conditions.
NOTE: Under cold temperatures, pedal effort will be higher than normal until the power steering fluid reaches operating temperature.