CONTROL KEYPAD, DEVICE FOR SENSING AND DIAGNOSING MALFUNCTIONS THEREOF, AND USE THEREOF FOR CONTROLLING A MOTOR VEHICLE SEAT

摘要

A keypad including a switch array between row conductors (l1-lm) and column conductors (c1-cn). Each row or column conductor is constantly shorted (18, 19, 20, 21) to at least one respective column or row conductor. The status of the switches (I1-I3, M, T1-T4) is sensed by sequentially applying a first (ground) voltage to the column conductors and sequentially sensing the resulting voltages on the row conductors polarized at a second voltage (+Vbat). The device includes a computer (2) for diagnosing a break in the circuit of a column conductor by responding to the sensed second voltage on any one of the row conductors during control at the first voltage of the column conductor constantly shorted to the row conductor.