GMC 25111880 Module Asm,Cruise Control

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Cruise control maintains a set vehicle speed in normal driving conditions. It mainly uses vacuum to run a throttle servo, overseen by the Cruise Control Module (CCM). Features include cruise, coast, resume/accelerate, and "tap up/down" speed adjustments. Activation typically starts above 25 mph (40 kph). Key components are mode switches, CCM, servo unit, Vehicle Speed Sensor (VSS), vacuum supply, release switches, and harnesses. The system retains vacuum at the set position, with the controller managing three vehicle/system states. Components include the vacuum servo, EMC Controller/Actuator, Electronic Module, and VSS, supplemented by a Vacuum Accumulator for consistent performance.

This cruising speed control system is optionally available on certain models and allows the driver to maintain a constant highway speed without the necessity of continual adjustment of foot pressure on the accelerator pedal. The system employs a servo unit connected to the intake manifold, a speedometer cable-driven regulator and various switches. An override capability is built in. Any malfunction in the performance of the system should first be checked out by inspecting the fuse, the security of the leads and terminals, and the vacuum pipes and connections. The following adjustments should then be checked and if necessary altered to conform to those specified. The servo operating rod which connects to the carburetor throttle linkage should be adjusted. The regulator can be adjusted by turning the orifice tube in or out (never remove it as it cannot be re-installed). If the vehicle cruises below the engagement speed, screw the orifice tube out. If the vehicle cruises above the engagement speed, screw the orifice tube in. Each¾ turn of the orifice tube will change the cruise speed by about 1 mph.Tighten the locknut after each adjustment. The brake release switch contacts must open when the brake pedal is depressed between ¼ and ½-in measured at the pedal pad. The vacuum valve plunger must clear the pedal arm when the arm is moved A inch measured at the switch. The column mounted engagement switch is non-adjustable, and is serviced only as part of the complete turn signal lever assembly. Faulty components should be replaced as complete assemblies after disconnecting electrical leads, vacuum hoses and control cables from them as necessary.

This cruising speed control system is optionally available on certain models and allows the driver to maintain a constant highway speed without the necessity of continual adjustment of foot pressure on the accelerator pedal. The system employs a servo unit connected to the intake manifold, a speedometer cable-driven regulator and various switches. An override capability is built in. Any malfunction in the performance of the system should first be checked out by inspecting the fuse, the security of the leads and terminals, and the vacuum pipes and connections. The following adjustments should then be checked and if necessary altered to conform to those specified. The servo operating rod which connects to the carburetor throttle linkage should be adjusted by turning the link on the rod until there is 0.02 to 0.04 inches of free play at the carburetor. The regulator can be adjusted by turning the orifice tube in or out (never remove it as it cannot be re-installed). If the vehicle cruises below the engagement speed, screw the orifice tube out. If the vehicle cruises above the engagement speed, screw the orifice tube in. Each ¼ tum of the orifice tube will change the cruise speed by about 1 mph. Tighten the locknut after each adjustment. The brake release switch contacts must open when the brake pedal is depressed between 0.38 and 0.64 inch measured at the pedal pad. The vacuum valve plunger must clear the pedal arm when the arm is moved j inch measured at the switch. The column mounted engagement switch is non-adjustable, and is serviced only as part of the complete tum signal lever assembly. Faulty components should be replaced as complete assemblies after disconnecting electrical leads, vacuum hoses and control cables from them as necessary.

Mount the module with the push-in retainers, connect the electrical harness to the module, install the left sound insulator, connect the negative battery cable, then reset the radio, clock, etc. as necessary.

Remove the left side sound insulator, disconnect the electrical harness from the module.

Cruise control is a speed control system which maintains the desired vehicle speed under normal driving conditions.

The system includes a servo unit connected to the intake manifold, a speedometer cable-driven regulator, and various switches.

The vehicle should be test driven to determine if the cruise control is now working.