Description & Operation
Instrument cluster uses analog type gauges which include: speedometer, tachometer/quartz chronometer, clock, fuel gauge, fuel economy indicator gauge (if equipped), oil pressure gauge, coolant temperature gauge, and LCD outside temperature display mounted under speedometer. Warning light bar indicators include; exterior light failure, front brake pad wear, low engine oil and engine coolant levels, and low windshield washer level. See Fig 1.
Supplemental Restraint System (SRS) and Anti-Lock Brake System (ABS), Automatic Slip Control (ASR), and Adaptive Damping System (ADS) malfunction warning indicators are also located in light bar.
Speedometer on 300SD is electronic, with the speed sensor located in rear of transmission. Speedometer on 300E and 300SE models is cable-driven with Hall Effect speed sensor located in rear of speedometer head.
Fuel and temperature gauges on all models use variable resistance sending units. The gauge panel containing the fuel gauge, fuel economy indicator gauge, oil pressure gauge, coolant temperature gauge and warning buzzer must be replaced as a complete panel assembly.
When ignition is turned on, SRS warning light illuminates along with other instrument panel lights. If no faults are in SRS, warning light will go out after about 4-10 seconds with engine off, or will go out immediately when engine is started.
If SRS warning light remains on, this indicates a fault exists in system. Light will remain on until fault is corrected and memory is cleared. If warning light fails to illuminate when ignition is turned on, bulb is faulty, and/or wire to bulb is shorted to ground. For further air bag information, see AIR BAG RESTRAINT SYSTEM article in the ACCESSORIES/SAFETY EQUIPMENT section.