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14. Onboard electric equipment

The elementary diagnostic equipment and examples of its application

How to make a lamp sampler

Lamp sampler of filament type

At service of systems of electric equipment the lamp sampler is the most effective tool for verification of conductivity of the contour which is under loading.

The elementary lamp sampler can be made of couple of pieces of a 4-millimeter wire, couple of clips like "crocodile" and the cartridge equipped with two contacts and a 1-nitevy lamp calculated on supply voltage in 12 V with a 2-contact socle (see an accompanying illustration).

1 — wires
2 — the boss
3 — a clip
4 — a lamp

 PERFORMANCE ORDER

  1. Smooth out wires since both ends at convenient length.
  2. Solder to one of the ends of each wire clips like "crocodile".
  3. Connect the opposite ends of wires to the boss's plugs, having tracked that they did not adjoin among themselves and to the boss's case.
  4. Establish a lamp by a socle in a cartridge.
  5. For check of serviceability of functioning of assembly connect clips to plugs of the 12-volt battery. The lamp has to light up at the same time.

Lamp sampler on a light-emitting diode

Use of a lamp sampler of usual type (with filament) for verification of conductivity in the chains including electronic components in the structure can lead to an exit of such components out of operation owing to course through them rather high current. Authors of this manual recommend to use in such cases a lamp sampler on the basis of a light-emitting diode (LED).

The elementary lamp sampler on a light-emitting diode can be made of a piece of a 3-millimeter wire of suitable length, a clip like "crocodile", a light-emitting diode and the resistor 1/4 of W, 560 Ohms. Besides the casing which is rather simple for making of an old ball pen and a thin metal core (a wire piece) pointed since one end is required. Track that connection of the anode and cathode of a light-emitting diode was made in accuracy as shown in an illustration.

1 — glue
2 — a light-emitting diode
3 — the diode cathode
4 — the diode anode
5 — the pen case
6 — a wire
7 — the resistor
8 — the probe (the pointed metal core)
9 — a clip

When using a lamp sampler on a light-emitting diode it is necessary to remember that the diode passes current only in one direction, therefore the lamp will function only in case the clip of a wire is connected to a negative side of a contour, and the probe - to positive.


 PERFORMANCE ORDER

  1. Solder a wire piece to the light-emitting diode cathode (the cathodic plug much well being in the neighbourhood with it at an end face of the diode of anode).
  2. Solder the resistor on 560 Ohms to the anode.
  3. Seal are short a wire piece between the resistor and the probe.
  4. Drill an opening in a wall of the case of a pen and release in it the wire going from the cathode.
  5. By means of glue fix the probe in the pen case, having pushed its end in the lower opening.
  6. To the cathodic wire which is released through a side opening solder a clip like "crocodile".
  7. The light-emitting diode can be fixed in the stopper which is densely entering the top opening of the case of a pen. For observation of the diode in a stopper a viewing opening has to be made.

How to make a wire crossing point

At diagnostics of malfunctions of components of systems of electric equipment it is very useful to have near at hand a wire crossing point.

 PERFORMANCE ORDER

  1. Smooth out the piece of a 4-millimeter wire suitable on length since both ends.
  1. Connect to both ends of a wire clips like "crocodile" (solder them, or fix in plugs by screws). Examples of wires crossing points of various length are shown on an accompanying illustration.
  1. Check a wire a crossing point for conductivity existence for what disconnect one of wires from the battery and connect a wire crossing point between the plug of the battery and a tip of a wire. Include ignition, - at the same time control lamps on the dashboard have to light up regularly.
  2. Remove a wire a crossing point and restore initial connection of the battery.

It is the best of all to make several wires crossing points of various length and with clips of various type in advance.

Check of serviceability of switches

If there are doubts in serviceability of functioning of the switch, disconnect from it an electrical wiring and by means of a lamp sampler check it for existence of food. If the switch is switched on in an ignition contour, for check it is necessary to turn a key in position of ON.

Having defined color and location of a power wire disconnect from it a lamp sampler, take a suitable wire crossing point and connect it between a power wire of the switch and a wire from its opposite side. If a contour as it should be, it is necessary to replace the switch.

Check of serviceability of lamps

At suspicion on refusal of a lamp take it from the boss, then connect one end of a small wire crossing point to the positive plug of the serviceable battery, and its second end - to a uvula on a lamp socle wall.

Connect one end of the second wire crossing point to the negative plug of the battery, press the second to contact of a lamp. The serviceable lamp has to light up.

If the lamp is equipped with two filaments, press the end of a wire crossing point to the second contact of a lamp. The lamp also has to light up. The faulty lamp should be replaced adequate to it on the power consumption and rated voltage of food.

Check of serviceability of an electric chain

If there are suspicions on refusal of an electric contour, give on it tension, having turned on the corresponding toggle-switches and switches.

Disunite any of plugs of a contour and connect one of lamp sampler wires to the power, or turned to the switch party of a deenergized chain. Connect the second wire of a lamp sampler to the mass of the car (to some screw or a bolt on the chassis, a body or the block of the engine). If the lamp does not burn, check a contour closer to the power supply or the switch.

If the lamp lights up, continue to carry out check, moving ahead towards the consumer of the electric power (the motor, a lamp, etc.).

The most optimum point of the beginning of check of a chain is the safety lock plug. Do not forget every time, passing to the following site of a chain to restore initial connection of the previous socket / terminal connection.