Mercedes of the S-class W202

1993-2000 of release

Repair and operation of the car

Mercedes W202
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Lubrication system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. System of ignition
+ 8. Fuel system
+ 9. Transmission
+ 10. Running gear
+ 11. Steering
+ 12. Brake system
+ 13. Body
- 14. Electric equipment
   14.1.2. Measuring devices
   14.1.3. Technology of measurements
   14.1.4. Checks of electric equipment
   14.1.5. Sound signal
   14.1.6. Replacements of safety locks
   + 14.1.7. Rechargeable battery
   + 14.1.8. Generator
   + 14.1.9. Starter
   14.1.10. Traction relay
   + 14.1.11. System of lighting
   14.1.12. Devices
   14.1.13. Dashboard
   14.1.14. Glow lamps on the dashboard
   14.1.15. Light switch
   14.1.16. Radio receiver
   + 14.1.17. Antenna
   14.1.18. Loudspeakers
   + 14.1.19. Rubber brushes of screen wipers
   14.1.20. Windscreen washer jets
   14.1.21. The washing nozzles of headlights
   14.1.22. Screen wiper and its engine
   14.1.23. Protect the car
   14.1.24. Anticreeping "immunodeficiency"
   14.1.25. Why headlights grow dull
   14.1.26. Galogenka
+ 14.2. Electrical circuitries

14.1.26. Galogenka


The main reason for bystry failure of halogen lamps in cars – the big current proceeding through a lamp at the time of inclusion as resistance of its thread in a cold state is many times less, than in heated.

In this regard it is recommended to limit starting current by means of the additional resistor which is switched on consistently with threads of an incandescence of halogen lamps. After inclusion of a lamp it is resistance it is short-circuited by means of the relay of tension established parallel to a lamp.

Lack of such devices is need of use of one or two electromagnetic relays, details not enough reliable, especially in the conditions of the car experiencing vibration. Besides, at the time of inclusion after all spasmodic increase of current, though up to the smaller size takes place, than at usual schemes of inclusion of lamps.

Experts developed the contactless device which is not demanding use of the relay and providing smooth increase of current in a lamp. The device consists of the additional R1 resistor, two VD1 and VD2 diodes and the electrolytic condenser C.

At inclusion of thread of passing beam on a clip 1 positive potential moves. At the same time the VD1 diode connects the condenser C parallel to lamp thread, and is consecutive with it – the R1 resistor.

At inclusion of thread of driving beam positive potential moves on a clip 2, and the condenser C is connected parallel to thread of driving beam via the VD2 diode.

At such scheme of connection tension on lamps of EL1 and EL2 increases smoothly.

Resistance of cold threads of usual automobile lamps of near and far light approximately 10 times less their resistance in a heated state. The constant of time of heating of thread of a lamp makes 0,0014–0,003 pages.

In the course of inclusion of a lamp it is necessary for an exception of unacceptably big current that the speed of increase in resistance of thread of a lamp was more than the speed of increase in tension. It is reached by installation of electrolytic condensers with a capacity of 4000-6000 мкФ, with a rated voltage of 25 V.

If to take this advice, then along with increase in service life of lamps also accumulator life because of decrease in starting current and increase in smoothness of its increase will be prolonged.

About the correct adjustment of headlights...

The correct adjustment of headlights belongs to culture of driving to a large extent, than to any technical problems. To Pokhty we will talk about why over time headlights begin to give dim light, perhaps, and sufficient on the desert highway, but absolutely inefficient on recovered, especially, if the counter flow is big.

Sometimes sin on the generator and the regulator of tension. There is a grain of truth: malfunctions of these devices are noticeable by the "movement" of a light stream as if submitting to quantity of turns of the engine. It is clear, that unimportant operation of the generator and regulator of tension influences not only on efficiency of headlights – first of all the accumulator, or not receiving a full-fledged charge, or, on the contrary, suffers – receiving it there is a lot from what electrolyte "boils". Headlights in this case play only an indicator role though excess tension strongly reduces a resource of lamps. Constant dim radiation arises for other reasons: or strongly the reflector becomes soiled or becomes covered by corrosion, or the dark raid on an internal surface of a flask of a lamp appears.

If durability of a reflector depends on many factors, then even quite serviceable lamp "gathers" a dark raid for some 30-50 thousand kilometers. Efficiency it in that case percent is 20 lower than new.

The reflector "lives" longer. In modern cars the reflector and glass of a headlight are, so to speak, an integrated whole that first of all provides the most optimum light bunch, and in the second – tightness. The lack of tightness promoted penetration in a headlight of dust which burned then on a reflector and reduced its luminous efficiency. The same happened also to the moisture which was actively condensed on a reflector that caused corrosion.

Tried to fight against corrosion in some improbable way about five years ago, filling in red brake fluid in a headlight. The fashion for this, rather harmful, than useful invention passed, but other extreme – plexiglass "points" on glasses appeared. Except that such protection reduces luminous efficiency, "smearing" the direction of beams, it vyzvat strong heating and an obgoraniye of a reflector. To what in that case use from the glass protected from stones if the reflector suffers, – it is not clear, especially as how it was already told, glass and a reflector nowadays represent an integrated whole? By the way, therefore there is no sense to buy "lens" separately: never to achieve good light from such headlight.

At last, as for adjustments. Even the most excellent headlights supplied with halogen lamps can be on the way useless if they are adjusted somehow. Not everyone and not always has an opportunity to make adjustment at the stand. Therefore very quite good results are yielded by the old, well tested ways of "house" adjustment. The car is installed on the flat platform, measure 30 meters and put on a mark, let us assume, a brick. One of headlights included on passing beam something is veiled, and in the second – rotate adjusting screws so that vertically to bring limit of illumination to the put brick. The same is done also with other headlight. Driving beam is regulated in the horizontal direction, but already without brick: here it is important to achieve that bunches from both headlights did not fork and did not meet in the middle.

Electric motor

The most widespread malfunction in electromotors – breakdown of isolation in windings. Let's say you parked the car on the parking, and "janitors" forgot to switch off. Three-four hours are enough that the winding burned through. Or left a rag in a podkapotny niche where drafts of screen wipers move. The motor gets jammed with the same result for its windings.

Sometimes isolation manages to be restored, having sustained an anchor in bank with engine oil. Slightly warmed up drying oil gives much bigger effect if to sustain in it an anchor in several stages, doing daily breaks for drying.

The same trouble – breakdown of a winding – overtakes also a windshield washer electric motor. There is it often from a carelessness of the car owner, ever the tank with water is empty, or liquid froze, or jets-raspryskivateli or the filter of the pump are "tightly" hammered, and in the block of safety locks in a chain of an electric motor there is "bug".

In general with safety locks it is better not to joke. It will allow to avoid not only the short circuit terminating sometimes in the fire but also it is easier to find malfunctions.

For the beginning motorist has to be gold governed: searches of the reasons of malfunctions of electric equipment need to be begun with the block of safety locks.

I remember when I bought the first in the life car, in shop paid attention that the control lamp of a charge of the accumulator burns. Then the assumption was born that, has to be, or generator brushes did not get used yet, or "makes a fool" tension regulator (at that time cars were completed with mechanical relays regulators of the Bulgarian production. Sometimes, they worked on "recharge", and the bulb lit up). Replacement of the relay regulator did not yield results: the generator just did not develop energy. Replacement of brush knot was useless too.

It was necessary to remove the generator, previously discharge from system cooling liquid and having dismantled the thermostat. Check of windings of the generator and "bridge" of diodes showed that everything is all right. Only then, having done all this unnecessary work on absolutely new car, I guessed to glance in the block of safety locks. Certainly. the corresponding safety lock in a chain of excitement of a winding of the generator just was not.

So if at you the generator failed, begin check with a safety lock. Even if it is whole, be not too lazy to smooth out zones of its contact. Only after that undertake directly the generator.

However you do not hurry with its dismantling and dismantle. At first check brush knot. Existence of large chips on brushes, their considerable wear or oiling can already serve as a generator cause of failure.

Pay attention to a condition of contact rings of an anchor which are visible in a window into which the brush knot is inserted. Scratches and grooves are removed by a grinding skin, then are polished. If these operations do not yield result, it will be necessary to undertake the vypryamitelny block, previously having disconnected wires from the rechargeable battery and the generator. Check of the block is made by means of a control lamp. The negative pole of the battery is brought to the generator case, positive – through a bulb – to a conclusion "30".

If the bulb lights up, so the vypryamitelny block is punched and it needs to be changed. Happens, however, that prbivat either positive, or negative gates of the block. But, perhaps, it is better not to press in these subtleties especially as separate replacement of gates does not practice.

At last, about a starter. It is, perhaps, one of the most durable knots of the car, though it "works" in the most severe conditions. Even when the engine, in a starter capitally is under repair, happens, change only brushes and smooth out contact rings.

The weakest point of a starter – the obgonny coupling, or "бендикс": in it, sometimes, persistent rollers scatter or lie. And then at launch of the engine only hum is heard: the starter rotates, but does not turn a motor flywheel. Sometimes washing of "bendiks" helps with kerosene or acetone. But handymen, as a rule, razvaltsovyvat a holder with rollers and or change all details of a holder, or carefully wash out them.

Other widespread malfunction is more connected not with a starter, and with oxidation or break of tips of the special wattled tire connecting the engine with a body, that is "weight" (the tire is located under the engine). In this case the starter publishes characteristic clicks or in general "is silent" if, of course, "silence" is not caused by other reason – a detachment plus conducting of the relay of a starter. Check is anyway necessary. If conductings of the relay on the place – undertake the tire. But if conductings nevertheless jumped out, do not try to insert it, without removing a starter – you will waste in vain time. The starter should be dismantled.