Not light bulb.

When the switch is not lit bulb. The following causes: the lamp burned out, there is no contact with the lamp socket, faulty switch, faulty electrical wiring. Verification is performed in the following sequence: disable switch and turns the lamp. If the filament is broken, then changed to a new lamp. If the lamp is not burned out, then turns the protective plug or switch off the circuit breaker and a screwdriver bit arches her tongue - the center pin chuck. If the bulb is not turned inside out of the cartridge, do not try to apply a lot of effort. Remove the plug or turn off the breaker and then carefully remove the "skirt" chuck with a lamp. Then unscrew the bulb. If this light bulb has moved away from the cap, then cap "baked onto. The latter, after removal of the bulb, you can turn out with pliers. If defective cartridge, and the lamp is not lit, then check the switch. To do this, remove the cover and inspect. If there is no visible damage to machinery and heavy burning of contacts, then check the power switch, shorting the pins with a piece of wire or a metal tool, but better - a test lamp, but in this case and the control light and checks will not burn in full glow. The warning lamp is a simple device: an ordinary electrical cartridge with attached to it with two runs of wire screw a bulb capacity of 15 - 40 watts. Temporarily control the lamp could serve as a desktop or portable lamp with the cover plug. If the switch is defective and, as the lamp is not lit, then the fault must be sought in the wiring. We are looking for it using the test lamp. If the terminals of the lamp voltage is, the faulty wiring a lamp. Next check the voltage in the junction box from which the voltage supplied to the lamp. If there is no tension, then the damage is in front of her, but if the voltage is, then after it. And so on until the damage has been found.