Movano intermittently loses electrical power and stalls due to the ignition switch

The symptoms are distinctive and easy to recognise: sometimes the dashboard does not illuminate when the key is turned, the warning lights briefly go out while driving, the engine may stop over a bump, and moving the key in the ignition restores power. This is not a control-unit or immobiliser fault but a worn electrical portion of the ignition switch, also called the ignition-switch contact unit. Its power contacts burn and lose continuity. After removal, the damaged terminals appear darkened or melted.

Why does it fail, and what should be replaced?

The electrical load passes through the ignition switch, and every turn of the key causes microscopic arcing at its contacts. Over the years, the oxide layer grows, resistance to current flow rises, the connection heats even more and the process accelerates. Repair consists of replacing the electrical switch alone, without replacing the complete ignition lock. This is worth knowing because some workshops immediately propose a broader and considerably more expensive repair. Confirm the precise work required on your vehicle before purchasing, however, as the procedure can vary in detail with the equipment version. The same electrical switch fits the Movano B (2010-2021) and Vivaro B (2014-2019). While replacing it, inspect the tightness and condition of the engine-bay earth connections, which can cause similar intermittent power loss.