Your Mercedes-Benz R107 is equipped with a sophisticated set of indicator lights and gauges, designed to provide crucial real-time information about your vehicle’s performance, safety, and maintenance needs. Knowing what each light means can help prevent mechanical failures, improve driving safety, and extend the lifespan of your classic car.
This guide will explain each indicator light, what it signifies, and what actions you should take when one illuminates.
1. ABS (Antilock Brake System) Indicator Light
What It Does
The ABS system prevents the wheels from locking up during braking, especially on slippery surfaces, allowing for better control and shorter stopping distances.
What It Means When Lit
- Upon startup: The ABS light comes on briefly when you turn the key to position 2, then goes out when the engine starts.
- While driving: If the light remains on or comes on suddenly, the ABS has detected a malfunction and has switched off. The normal brake system will still function, but without antilock assistance.
Actions to Take
✅ Check battery voltage: If voltage drops below 10 volts, the ABS system may turn off temporarily.
✅ Restart the car: If the light stays on, restart the engine to see if it resets.
✅ Visit a Mercedes-Benz specialist: If the ABS light remains illuminated, the system needs immediate professional inspection.
2. Brake Pad Wear Indicator Light
What It Does
This light monitors the thickness of your front brake pads and warns you when they are worn down.
What It Means When Lit
- If the light illuminates during braking, your front brake pads are worn and need replacement.
Actions to Take
✅ Schedule a brake inspection immediately—worn pads reduce braking efficiency and could damage the rotors.
3. Brake Warning Light
What It Does
This light warns you of insufficient brake fluid levels or an issue with the brake system.
What It Means When Lit
- If the light turns on while driving, your brake fluid level is too low.
- If the light stays on after topping off brake fluid, there may be a leak or worn brake components.
Actions to Take
✅ Check the brake fluid level in the reservoir and refill if needed.
✅ Inspect for leaks under the car or around brake lines.
✅ Do not drive if the brakes feel weak or spongy—seek professional assistance.
4. Charge Indicator Light (Battery Warning Light)
What It Does
This light monitors the charging system, including the alternator, voltage regulator, and battery.
What It Means When Lit
- If the light stays on after starting or turns on while driving, it indicates a charging system failure.
- This could mean a failing alternator, loose belt, or bad battery.
Actions to Take
✅ Turn off non-essential electronics (radio, heater, A/C) to preserve battery life.
✅ Check battery terminals for corrosion or loose connections.
✅ Visit a mechanic to test the alternator and battery as soon as possible.
5. Oil Pressure Gauge & Low Oil Level Indicator
What It Does
The oil pressure gauge measures the pressure in your engine’s lubrication system, while the low oil level light warns of dangerously low oil levels.
What It Means When Lit
- If the oil pressure gauge reads low at idle but rises when accelerating, this is normal.
- If the oil pressure does not rise when you rev the engine or the low oil level light turns on, you may have an oil leak, low oil, or engine wear.
Actions to Take
✅ Check the oil level with the dipstick immediately and refill if needed.
✅ Inspect for leaks under the vehicle.
✅ Do not drive with low oil pressure—this could cause catastrophic engine damage!
6. Exterior Light Failure Indicator
What It Does
This light alerts you if one or more exterior lights (headlights, brake lights, turn signals) are not functioning.
What It Means When Lit
- If the light turns on when activating a turn signal or brake light, a bulb has burned out.
- The system can also detect incorrectly installed or non-compatible bulbs.
Actions to Take
✅ Check and replace any faulty bulbs.
✅ Ensure you use the correct wattage—incorrect bulbs can trigger the warning light.
7. Fuel Reserve Warning Light
What It Does
Alerts you when the fuel level drops to the reserve amount (3.0 gallons / 11.5 liters).
What It Means When Lit
- You are running low on fuel and should refuel soon.
Actions to Take
✅ Refuel as soon as possible to prevent running out unexpectedly.
8. Coolant Temperature Gauge & Low Coolant Level Indicator
What It Does
Monitors engine temperature and coolant levels.
What It Means When Lit
- If the temperature gauge reaches the red zone, the engine may be overheating.
- If the low coolant light comes on, the coolant level is too low.
Actions to Take
✅ Turn off the engine immediately if overheating.
✅ Allow the engine to cool before opening the radiator cap—hot coolant can cause severe burns.
✅ Check for coolant leaks and refill with MB-approved coolant if needed.
9. Windshield Washer Fluid Level Indicator
What It Does
Warns when washer fluid is low.
Actions to Take
✅ Refill with MB Windshield Washer Concentrate “S” to prevent freezing in winter.
10. Outside Temperature Indicator
What It Does
Displays the current outside temperature.
Important Notes
⚠️ Does NOT serve as an ice-warning device—roads may still be icy even if temperatures appear above freezing.
Actions to Take
✅ Always use caution when temperatures are near freezing.
11. Emission Control & “Check Engine” Light (California Models Only)
What It Does
The Check Engine light warns of malfunctions in the emission control system.
What It Means When Lit
- A sensor, catalytic converter, or fuel system component may be faulty.
Actions to Take
✅ Have the car diagnosed using an OBD scanner.
✅ Do not ignore this light—unresolved emission issues can reduce fuel efficiency and damage the engine.
12. Economy Indicator (ECONOMY Gauge)
What It Does
Shows fuel consumption trends based on driving style.
Actions to Take
✅ Keep the pointer in the black area for optimal fuel efficiency.
✅ Use higher gears when possible to lower fuel consumption.
Conclusion
Your Mercedes-Benz R107 is equipped with an intelligent set of indicators and warning lights to keep you informed about your car’s condition. Understanding and responding to these signals can help prevent breakdowns, improve safety, and protect your classic vehicle’s longevity.
If any indicator remains illuminated or behaves abnormally, seek professional assistance as soon as possible.
