2008-Up H2 Hummer High Idle Controller HIC875 Installation

Refer to the wiring diagram on the following pages 1. Disconnect the connector going into the accelerator pedal. Plug the male connector of the HIC875 into the accelerator pedal socket. Plug the vehicle’s accelerator pedal connector into the female connector of the HIC875. IMPORTANT!!!! Route the power wires (RED and BLACK ) away from the accelerator pedal wire harness. The wires should not come in contact with the harness. Do not zip tie any wires to the accelerator pedal wire harness. This might cause an unstable RPM level when the high idle is activated. Connect the RED wire from the HIC875 to 12V ignition on single alternator systems. On models with a built in voltage monitor (HIC875-VM) connect the RED power wire to the battery system to be monitored. For single alternator connect to 12V ignition. For dual alternator systems connect after the secondary battery solenoid. This wire provides power and is used to sense battery voltage on the –VM model. For automatic transmissions connect the BLACK wire from the HIC875 to a good ground. For manual transmissions connect the BLACK ground wire to the wire coming off the parking brake switch. High idle will only be enabled if the parking brake is set.
2. Connect the BLUE tach signal wire to the white wire with black stripe coming out of the bottom ECM X2 connector pin 68. The ECM is located on the driver’s side at the front of the engine compartment. Test this wire first, it should read about 2.5 volts DC with the engine running and will read frequency equal to engine rpm. Solder and seal this connection.
3. Green Interlock wire: For automatic transmissions see the interlock wire connection procedure on the following page. For 2007 and newer GM, except Hummer H2, the Green interlock wire connects to the shift lock solenoid located at the steering column. High idle will only be enabled with the vehicle in PARK and is disabled when the vehicle is taken out of PARK. Depressing the brake pedal (with vehicle in PARK) will disable the high idle. Tapping the brake pedal will reset the high idle system. For 2008 and newer Hummer H2 the Green interlock wire connects to the Green wire of the interlock relay module. See following page. High idle will only be enabled with the vehicle in PARK and the parking brake set.

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