Mercedes S-Class W-140

1991-1999 of release

Repair and operation of the car

Check of system of charging

If you found malfunction in system of charging - malfunction of the generator cannot be the only cause. Execute the following checks:

   a) Examine a driving belt and be convinced that it is tense and is not damaged. At detection of damages replace it (address the Head Routine maintenance).
   b) Make sure that bolts of fastening of the generator are reliably tightened;
   c) Check conducting of the generator and all sockets. All contacts have to be reliable and not oxidized;
   d) Check the corresponding safety locks located in a motive compartment (address the Head Onboard electric equipment). At detection burned down remove the cause of burn-out of a safety lock and replace it (at burn-out of the corresponding safety lock you will not be able to start the engine or to include any of devices);
   e) Start the engine and be convinced that from the generator foreign sounds are not distributed (whistle or squeal can signal about malfunction of bearings or wear of brushes);
   f) Make sure that the rechargeable battery is completely charged. If one of cans is damaged, the rechargeable battery can consume excess current;
   g) Disconnect tips of wires from the rechargeable battery (at first negative). Examine plugs of the rechargeable battery and tips of wires. At detection of traces of corrosion carefully clear them (address the Head's materials Routine maintenance). Attach tips of wires to plugs and reliably tighten.

Measure tension on plugs of the rechargeable battery at the switched-off engine. It has to be about 12 Century.

Attach the voltmeter to poles of the rechargeable battery and start the engine. Increase turns until stable tension is established. Indications of the voltmeter have to lie ranging from 13.5 up to 14.6 Century.

Turn on as much as possible electric devices (headlights, the heater fan, heating of back glass, etc.) and be convinced that the voltmeter shows from 13 to 14 V. Napryazheniye can fall, but has to increase again (for this purpose you, perhaps, should increase slightly engine turns).

If tension on the voltmeter exceeds the specified sizes, replace tension regulator.

If tension on the voltmeter is lower maximum admissible, then as a cause of defect worn-out brushes, weak springs of brushes, failure of the regulator of tension, the burned-down diode, break can serve in a winding, and also malfunction of rings of a collector. The condition of brushes and rings can be checked, but if nothing changes, the generator has to be removed for conducting check, repair or replacement.