Start blocker — general information (Mercedes-Benz Sprinter 903)

For safety reasons, cars can be equipped with a start interlock, which allows the engine to be started only when the gear selector lever is in position P or N. The interlock switch, located on the left side of the gearbox, interrupts the circuit (purple-white wire, contact connector "50") between the ignition switch and the starter when trying to start with the gear engaged.

If the engine does not start when you turn the ignition key, there may be a fault in the wiring or the switch itself. The following check can be performed:

• brake the car with the parking brake;
• turn the key in the ignition switch to the "start" position and simultaneously shift gears with the gear selector;
• if the engine does not start, use a piece of wire to make a jumper from the positive terminal of the battery directly, bypassing the switch, to the "50" contact connector. The starter should start working.

Caution! During this operation, it is imperative to set the gearbox selector lever to position N or P, and apply the parking brake to prevent the vehicle from moving when the engine is started.