Instruments and Controls Identification Group 54 of the Heavy-Duty Trucks Service Manual. for example, "F37." Fault codes are also stored in a history file for later viewing. For engine fault code instructions, see "Fuel Tach Gauge" in this chapter. However, the single gel cell, like any other single bat- tery, has limited current-supply capability, and will drain down faster than a standard multiple-battery installation that has no battery isolator system. Avoid ultra-deep discharging. Repeated ultra-deep dis- charging of a gel cell will reduce its life significantly.
The "Reset" toggle switch cancels the information in memory used for calculating average miles per gal- lon and erases the fault code history file. To reset, press and hold the reset switch. The average MPG reading slowly blinks on and off for about 10 sec- onds, indicating that you are in the reset mode. After erasing the memory, the display blinks "Er" until you release the reset switch. If you release the reset switch before the display changes to "Er," the engine fault code history will be displayed and the memory will not be erased. After being reset, the display will show "0" MPG until you drive at least 150 feet (46 m).
To protect against ultra-deep discharging, a low volt- age warning alarm and indicator light activate when the battery voltage falls to 12.0 volts or less. To si- lence the alarm, turn off all cab electrical loads or start the engine. Fuel-Tach Switch, Optional The FloScan Fuel-Tach is an electronic monitoring system that records fuel consumption and displays average miles per gallon. The Fuel-Tach gauge pro- vides you with immediate feedback, showing a per- centage difference between the current fuel con- sumption rate and the total trip miles per gallon average. Fog Light Switch, Optional The fog light switch ( Fig.
2.9 ) operates the fog lights, mounted on the bottom edge of the front bumper or recessed into the front bumper. The system is controlled by a toggle switch. See Fig. 2.8 . 1 2 3 4 5 01/18/95 f600071a 1. Fog Light Switch 2. Utility Light Switch 3. Panel Lamp Control Knob 4. Headlight/Parking Light Switch 5. Marker Light/Taillight Interrupt Switch 01/18/95 f600070b Fig. 2.8, Fuel-Tach Switch, Optional With nonelectronically controlled engines the "On" position allows you to receive average miles per gal- lon information for specific periods of time. In this position, the Fuel-Tach system stays on and stores the average miles per gallon information in memory, even if the engine is shut down.
Fig. 2.9, Light Controls For vehicles built to operate in the United States, the low beam headlights must be turned on before the fog lights can be turned on. The fog lights won’t go on if the high beam headlights are already on, and switching from low beams to high beams will switch off the fog lights. In the IGN position, the Fuel-Tach system is on only when the ignition switch is on. Shutting down the en- gine cancels the information in memory. For vehicles built to operate in Canada, the taillights and clearance lights must be on before the fog lights can be turned on.
Unless the headlight switch is all the way up (headlights, taillights, clearance lights, marker lights, and panel lights on) or down (taillights, clearance lights, marker lights, and panel lights on), the fog light switch will not turn on the fog lights. With electronically controlled engines the digital dis- play normally shows trip average miles per gallon. If the engine datalink sends an electronic fault code, the Fuel-Tach interrupts the miles per gallon display for 60 seconds, showing an "F" plus the fault code, 2.7