Speedometer Module: Description and Operation

The speedometer, odometer and trip odometer displays receive a signal from the digital ratio adapter through the LT BLU/BLK(824) wire. The digital ratio adapter converts the speed signal from the vehicle speed sensor to 4000 pulses per mile. A different digital ratio adapter is used for each axle ratio to convert the signal.

The speedometer indicates vehicle speed in miles per hour or kilometers per hour depending on E/M switch position. Speeds below 1.4 mph may be displayed a zero.

The odometer/trip odometer display is mounted on a separate board attached to the main display board. The odometer displays the total vehicle milage up to 999,999 miles in the English mode. If the milage exceeds this, the display will flash ERROR. In the metric mode, the display will flash ERROR when it exceeds 999,999 kilometers. The English display will still show the normal display.

The display can be switched from total odometer to trip odometer by pushing the TRIP button. When the switch is open, the total milage is displayed. When the TRIP switch is closed, the trip milage is displayed.

The trip odometer can be reset to zero by pushing the RESET button. The display must be in the TRIP mode to be reset.

The accumulated mileages of the two displays are stored in a nonvolatile memory chip to prevent losing this data if the battery or cluster is disconnected.

If the cluster is replaced, The odometer display can be transferred to the new cluster.