Natural Gas Cluster

INSTRUMENT CLUSTER - NATURAL GAS VEHICLE

NOTE: The natural gas vehicle (NGV) instrument cluster is diagnosed and repaired the same way as the gasoline vehicle conventional instrument cluster.

The NGV instrument cluster consists of the following components:
- speedometer
- engine coolant temperature and oil pressure gauge assembly
- fuel and battery voltage gauge assembly
- transmission range indicator
- warning indicators
- instrument cluster printed circuit
- low fuel level warning switch

PRINCIPLES OF OPERATION

WARNING:
- Do not modify the system configuration or components or install new components with parts not specially designed for use with natural gas. Ford motor company has specially designed the materials, components and system configuration for the 4.6L (2V) Crown Victoria natural gas vehicle, and each particular system is precisely calibrated for efficient operation. The use of different parts or materials can produce an untested configuration that could result in fire or personal injury or cause engine damage.
- It is important that your natural gas vehicle be correctly maintained by Ford natural gas trained personnel. If a concern occurs, it is important that correctly trained personnel diagnose the cause. If the problem relates to the fuel system, correct part replacement is imperative to keep your vehicle operating at normal performance. Natural gas components and gasoline fuel components are not interchangeable. If your vehicle is not repaired in accordance with natural gas-fueled vehicle procedures, damage can occur and your warranty may be invalidated.

NOTE:
- All standard production components and systems receive routine repairs under base warranty procedures.
- For diagnosis and testing of non-NGV related instrument cluster functions, refer to Conventional Cluster.

Fuel Level Indication System
The natural gas vehicle (NGV) fuel level indication system consists of the following components:
- an NGV module
- a fuel tank pressure sensor
- two fuel tank temperature sensors (No. 1 [upper] and No. 2 [lower])
- a fuel gauge (located in the instrument cluster)
- a low fuel level warning switch (located on the back of the instrument cluster)

Low Fuel Level Warning Switch
The low fuel level warning switch:
- is designed to reduce fuel gauge pointer fluctuation.
- provides a low fuel warning when the fuel gauge indicates approximately 1/16 full.

Natural Gas Vehicle (NGV) Module
The NGV module assembly:
- consists of a 60-pin module, a bracket, a marine cover and four marine cover retainers.
- houses the unique electronics required for natural gas fuel systems.
- is located on the center radiator support, behind the radiator grille.

The NGV module carries out the following functions:

- NOTE: No injector calculations are carried out; the injector driver output is not determined by the NGV module.

injector drivers: the NGV module accepts eight unmodified injector signals from the powertrain control module (PCM) and allows a peak-and-sustain current to flow through the injector solenoids.

- fuel gauge driver: the NGV module uses fuel tank temperature and fuel tank pressure inputs to calculate the density of the fuel; a look-up table is used to determine the output signal to the low fuel warning switch (through a combination of discreet resistors), which drives the fuel gauge located in the instrument cluster.
- power and ground supply: the NGV module supplies power to the instrument cluster components on circuit 231 (BK/YE) when the ignition switch is in the RUN and START positions. Ground for the fuel gauge, the low fuel level warning switch and the voltmeter is supplied on circuit 570 (BK/WH), circuit 231 (BK/YE) also supplies power to the following components in the instrument cluster:
- low fuel indicator
- CHECK ENGINE indicator (malfunction indicator lamp)
- speedometer
- temperature gauge
- oil pressure gauge
- anti-lock braking system (ABS) indicator
- overdrive (OD) OFF indicator
- brake warning indicator
- AIR BAG warning indicator
- fail-safe cooling indicator

Fuel Tank Pressure Sensor
The fuel tank pressure sensor:
- contains integral solid state circuitry that outputs a voltage signal that is proportional to pressure.
- has an output that is linear from 0 kPa (0 psi) up to 27,579.03 kPa (4000 psi).
- is located in the upper tank vent box on the upper tank rack.

Fuel Tank Temperature Sensors
The fuel tank temperature sensors:
- change resistance in response to the temperature of the fuel in the fuel tank; as the surrounding temperature increases, the resistance decreases (the voltage signal also decreases).
- provides a signal to the NGV module that indicates the temperature of the fuel.
- are located next to the fuel tanks, one in the vent box at Fuel Tank No. 1 (Fuel Tank Temperature Sensor No. 1) and one below the vehicle at Fuel Tank No. 4 (Fuel Tank Temperature Sensor No. 2).