The reverse gear has disappeared, and the rearview camera stopped working in my Mercedes ML- and GL-class W164.
The rearview camera started functioning intermittently. To check the reverse light, I turned on the ignition, shifted into reverse, and noticed the light wasn't on. The fuse was intact. I measured the voltage at the connector – the power was present. I removed the bulb – it was working. Once I pulled the bulb from the socket, the camera began to work, and an image appeared on the mirror. Inserting the bulb back, the camera stopped working, and the reverse light didn't illuminate. Removing the bulb again made the camera function properly. The power at the socket was confirmed. Testing the bulb on a battery showed it was operational. Trying a different bulb yielded the same results.
In Mercedes ML- and GL-class W164 vehicles, the rear SAM unit is responsible for controlling headlight illumination, turn signals, and processing data from various dashboard sensors. This unit often receives criticism from specialists who see it as a flawed solution by Mercedes-Benz.
Malfunctions in the rear SAM module can lead to the following issues for vehicle owners:
- Rear lights not working;
- Incorrect fuel gauge readings;
- Rear door not opening;
- Fuses blowing frequently;
- Rapid battery drain;
- Display indicating bulb failures.
Accurate diagnostics can help identify the root cause of these issues. Various errors may be detected, related to bulbs, trunk components, terminals, and fuel level sensors, such as: 9096 — Output circuit 15R; short to ground; intermittent signal. 9107 — Right brake light; short to positive or circuit break; intermittent signal.
