Starter fault diagnostics (Mercedes-Benz S-Class W126)

If the starter does not turn, then first of all you should check whether there is the required voltage of 8 V at the terminal 50 of the electromagnetic valve. If the voltage is less than the specified level, you will need to check the wires in the starter circuit using the electrical equipment diagram. Whether the starter will retract at full battery voltage can be checked as follows:

Do not engage low gears, turn on ignition.

With thick wire (cross-section not less than 4 sq. mm) connect the clamps (30) and (50) of the starter. If the starter engages correctly, the defect is in the starter wire. If the starter does not engage, it will need to be removed and checked.

Test conditions: Wire connections must be securely fastened and not oxidized.