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.
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 350 Series, 420SEL and 560 Series models is electronic, with the speed sensor located in rear of transmission. Speedometer on other models is cable driven with Hall Effect speed sensor located in rear of speedometer head. The 190E uses a manual oil pressure gauge with capillary tubing running from engine to gauge. All other models use an electric oil pressure sending unit.
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 warning light remains on, this indicates a fault in system. When SRS detects a fault, warning 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 BAGS article in the ACCESSORIES/SAFETY EQUIPMENT section.