Product Listing

HIC 700 Voltage Monitor

The HIC 700 Voltage Monitor is used in conjunction with the factory Fast Idle function on GM C-series medium duty trucks to automatically engage a High Idle when insufficient alternator output causes the battery voltage to drop.

Interfaces with:

2003 and newer Chevy and GMC C-Series Kodiak and Topkick Medium Duty trucks (4500, 5500, 6500, 7500 & 8500) with the Duramax engine.


The HIC700 monitors battery voltage and activates automatically if it drops below 12.6V for 10 seconds.  When this is detected, the voltage monitor will send a signal to the vehicle’s computer to engage the fast idle and illuminate the green led.

In order for the HIC700 to function, the UF3 fast idle option must be ordered on the vehicle, or it must be activated and adjusted with a Tech2 scan tool.  This tool will allow the technician to adjust the factory preset parameters to the desired settings.  An increased idle speed of 1300 RPM provides sufficient alternator output.

Conditions for High Idle operation:

  1. Engine must be running
  2. Transmission must be in Park or Neutral
  3. Vehicle’s speed must be less than 5 mph
  4. Brake or Clutch must not be depressed

The operator can also activate the fast idle mode by pressing the fast idle switch. If the switch is pressed while the engine is in the fast idle mode, the engine will return to normal base idle.

Common Uses:

Command Vehicles
Emergency Response Vehicles
Shuttle Buses
Prisoner Transport Vehicles