| 1. Disconnect pressure from a chain and check up a chain on integrity by means of a bulb with the connected power supply. |
| 2. Connect bulb wires to the chain ends (or by the positive end and weight of the car); if the control bulb lights up, in a chain there are no ruptures. |
| 3. If the bulb does not light up, means, somewhere in a chain there is a rupture. |
| 4. Precisely also it is possible to check up the switch, having connected a control bulb to switch plugs. |
| 5. After switch inclusion, the control bulb should light up. |