System Description, Console & Sensors Information

FIGURE 1 - SYSTEMS SENTRY CONSOLE:

FIGURE 2 - FLUID LEVEL AND WEAR SENSORS:

SYSTEM DESCRIPTION

Systems Sentry is an electronic warning system that monitors vital fluid levels and disc brake pad wear. The system consists of a warning light console (A) mounted on the driver's side of the instrument panel (Fig. 1), fluid/wear level sensors mounted in the various components being monitored (Fig. 2), and the necessary interconnecting wires. A 3 amp signal fuse is also included in the disc brake pad warning circuit.
The system monitors the following items:

^ Engine oil level

^ Transaxle fluid level

^ Engine coolant level

^ Power steering fluid level

^ Brake fluid level

^ Windshield washer fluid level

^ Front disc brake pad wear
Console

Three different color warning lights are used in the instrument panel mounted console.

Amber checking light indicates that each of the various fluid and wear levels are being monitored.

A green light indicates that the fluid or wear level is OK.

A red light indicates that the fluid or wear level must be checked and corrected if necessary.

A preprogrammed electronic monitor unit in the warning light console analyses electrical signals sent by the sensors. These signals vary depending upon fluid or wear level. An OK level generates a different signal from that of a low level. The monitor unit analyses the signals received during the checking process and triggers the appropriate console light.


Sensors

The sensors are mounted directly in the component being monitored.

Sensor locations are as follows:

^ Engine Oil - in oil pan facing front of the vehicle just below oil sender switch.

^ Manual Transaxle - in transmission fill plug.

^ Automatic Transaxle - on (and part of) transmission dipstick.

^ Brake Fluid - in master cylinder.

^ Power Steering Fluid - in fluid reservoir.

^ Engine Coolant - in coolant recovery bottle.

^ Windshield Washer Fluid - in washer reservoir.

^ Front Disc Brake Pads - in each inboard brake pad.


The engine oil and transaxle fluid sensors operate on the principle of changes in thermal conductivity and resistance caused by immersion or non-immersion in a fluid.

The power steering, windshield washer, brake fluid and engine coolant sensors are float-type switches triggered by changes in fluid level.

The brake pad wear sensor is an electro-mechanical device actuated by contact with the rotor surface. When pad wear allows sensor-to-rotor contact, the sensor grounds against the rotor causing a brief current surge in the pad warning circuit. The surge blows the 3 amp in-line signal fuse causing an open in the circuit. The electronic monitor interprets the signal and triggers the red warning light in the console.

NOTE: The 3 amp signal fuse must be replaced along with the sensors and brake pads before the console warning light will go off.