S-class W202 Mercedes

1993-2000 of release

Repair and car operation

W202 Mercedes
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Greasing system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. Ignition system
+ 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. Equipment of measurements
   14.1.4. Electric equipment checks
   14.1.5. Sound signal
   14.1.6. Replacements of safety locks
   + 14.1.7. Storage battery
   + 14.1.8. Generator
   + 14.1.9. Starter
   14.1.10. Traction relay
   + 14.1.11. Lighting system
   14.1.12. Devices
   14.1.13. Dashboard
   14.1.14. Filament lamps on the dashboard
   14.1.15. Light switch
   14.1.16. Radio receiver
   + 14.1.17. Aerial
   14.1.18. Loudspeakers
   + 14.1.19. Rubber brushes of screen wipers
   14.1.20. Jets of a stekloomyvatel
   14.1.21. 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. "Galogenki"
+ 14.2. Electroschemes

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14.1.26. "Galogenki"


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

In this regard it is recommended to limit a starting current by means of the additional resistor which has been 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 the tension established parallel to a lamp.

Lack of such devices is need of use of one or two electromagnetic relays, details insufficiently reliable, especially in the conditions of the car testing vibration. Besides, at the moment of inclusion spasmodic increase of a current, though to smaller size after all takes place, than at usual schemes of inclusion of lamps.

Experts developed the contactless device not demanding use of the relay and providing smooth increase of a 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 a thread of a passing beam on a clip 1 the positive potential moves. Thus the VD1 diode connects the condenser C parallel to a lamp thread, and is consecutive with it – the R1 resistor.

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

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

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

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

If to use these councils, along with increase in service life of lamps accumulator life because of decrease in a starting current and increase in smoothness of its increase will last also.

About the correct adjustment of headlights...

The correct adjustment of headlights in a bigger measure belongs to culture of driving, rather than to any technical problems. To Pokhtoma we will talk about why over time headlights start to give dim light, probably, and sufficient on the desert highway, but absolutely inefficient on recovered, especially, if the counter flow is great.

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

If the durability of a reflector depends on many factors, even quite serviceable lamp "gathers" a dark raid for any 30-50 thousand kilometers. Its efficiency in that case percent on 20 below the new.

The reflector "lives" more long. 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 a dust which burned then on a reflector and reduced it светоотдачу. The same occurred and to the moisture which was actively condensed on a reflector that caused corrosion.

About five years ago against corrosion tried to fight in any improbable way, filling in in a headlight red brake liquid. The fashion on this which is rather harmful, rather than passed a useful invention, but there was other extreme – plexiglass "points" on glasses. Besides, that such protection reduces светоотдачу, "smearing" the direction of beams, it вызвает strong heating and a reflector obgoraniye. What in that case use from the glass protected from stones if the reflector suffers, – it is not clear, as how it was already told, glass and a reflector nowadays represent an integrated whole? By the way, therefore it is no point to buy "lens" separately: good light from such headlight never to achieve.

At last, as to adjustments. Even the most excellent headlights supplied with halogen lamps, can appear on the way useless if they are adjusted somehow. Not everyone and not always has a possibility to make adjustment at the stand. Therefore very quite good results give the old, well tested ways of "house" adjustment. The car establish on an equal platform, measure 30 meters and put on a mark, let us assume, a brick. One of the headlights, included on a passing beam, something veil, and in the second – rotate adjusting screws so that limit of illumination vertically to bring to the put brick. The same do and with other headlight. A driving beam regulate in the horizontal direction, but already without a 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 – isolation breakdown in windings. Let's say you put the car on parking, and to switch off "yard keepers" forgot. It is enough three-four hours, 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 some stages, doing daily breaks for drying.

The same trouble – winding breakdown – overtakes also the electromotor of a washer of a windscreen. There is it often from a carelessness of the car owner when or the tank with water is empty, or liquid froze, or jets-raspryskivateli or the pump filter are "tightly" hammered, and in the block of safety locks in a chain of the electromotor 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 a fire, but also it is easier to find malfunctions.

For the beginning motorist should be gold governed: it is necessary to begin searches of the reasons of malfunctions of electric equipment with the block of safety locks.

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

It was necessary to remove the generator, previously plums 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 it was not simple.

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

However do not hurry with its dismantling and dismantle. At first check shchetochny knot. Existence of large chips on brushes, their considerable wear or a zamaslivaniye 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 shchetochny knot is inserted. Scratches and grooves are deduced by a grinding skin, then are polished. If these operations do not give result, it will be necessary to undertake the vypryamitelny block, previously having disconnected wires from the storage battery and the generator. Check of the block make by means of a control lamp. The negative pole of the battery is deduced on the generator case, positive – through a bulb – on a conclusion "30".

If the bulb lights up, means, the vypryamitelny block is punched and it needs to be changed. There are, however, that прбивает either positive, or negative gates of the block. But it is perhaps better not to press in these subtleties, as separate replacement of gates does not practise.

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

The weakest place of a starter – the obgonny coupling, or "бендикс": in it, it happens, scatter or there lie persistent rollers. And then at start-up of the engine hum is heard only: the starter rotates, but does not turn a motor flywheel. Washing "бендикса" sometimes helps with kerosene or acetone. But handymen, as a rule, развальцовывают I will embrace with rollers and or change all details of a holder, or carefully them wash out.

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 plusovy conducting of the relay of a starter. Check is anyway necessary. If relay conductings on a place – undertake the tire. But if conductings nevertheless jumped out, do not try to insert it, without removing a starter – will waste in vain time. The starter should be dismantled.