| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect disconnection of a direction indicator lamp in a trailer side without providing a connected signal switch, in a tractor towing the trailer. SOLUTION: Direction indicator lamps 5a to 5d in a tractor side are turned on and off by using an electromagnetic relays 11, 12, 15, 16, and direction indicator lamps 7a, 7b in a trailer side is turned on and off by using MOSFET 18, 19. In this case, when turning on and off the direction indicator lamps 5a to 5d, 7a, 7b by the operation of a direction indicator switch 3, a controller 2 detects disconnection of either one of the direction indicator lamp 7a, 7b on the basis of a voltage level of an output terminal side of the MOSFET 18, 19 when the direction indicator lamps are off, and detects disconnection of the direction indicator lamps 5a to 5d by a signal from a disconnection judging circuit 24 when the direction indicator lamps are on.</p> |
