Mercedes-Benz W164 rear SAM unit water damage
ML 320 CDI
Where does water get into the W164 rear SAM unit?
The most common leak point is the tail light seal, which can leak even if the light has not been removed. Water runs onto the tailgate lift motor and the rear SAM control unit (electrical system control unit) and oxidises the connectors.
What symptoms point to water damage in the W164 rear SAM?
Tail lights, indicators and brake lights stop working or stay on, the tailgate does not close properly and the tailgate motor buzzes. The diagnostic tool may show several bus and voltage fault codes even though the fuses are fine.
How is water damage to the W164 rear SAM repaired?
The connectors and the control unit circuit board are cleaned of corrosion, and the leaking tail light seal is replaced. A newer, thicker seal may stop the leak. The leak point should always be checked whenever the SAM unit is examined.
Related articles
Mercedes-Benz W164 7G-Tronic limp mode and conductor plateMercedes-Benz W164 7G-Tronic automatic gearbox slippingMercedes-Benz W164 boost pressure actuator and power limitation (limp mode)Mercedes-Benz W164 EGR valve faults and fault codesMercedes-Benz W164 Airmatic compressor does not lift the carMercedes-Benz W164 Airmatic suspension sagging and height sensor faultsMercedes-Benz W164 driveshaft support bearing failure: symptoms and replacementMercedes-Benz W164 transfer case chain and rattle