Malfunction detector for acceleration sensor

An apparatus for detecting a malfunction of any of a plurality of acceleration sensors used in an antilock control system, each of the acceleration sensors normally operative to output a first signal when a deceleration exceeding a predetermined threshold is present and a second signal when a deceleration of less than the predetermined threshold is present, the antilock control system including locking state processing circuitry for detecting a locking state of vehicle wheels and for outputting brake pressure control commands, said apparatus comprising:

• a test means for testing the acceleration sensors;
• a changeover means for selectively applying output signals from the acceleration sensors to one of said test means and the locking state processing circuitry;
• and,
• a lamp operatively coupled to said test means,
• wherein said test means includes (1) means for receiving the output signals from the acceleration sensors via said changeover means, (2) a plurality of state changeover means corresponding to said respective acceleration sensors for changing their outputs from 0 to 1 if the outputs of said respective acceleration sensors change from low deceleration state to high deceleration states and from 1 to 0 if the outputs of said respective acceleration sensors change from high to low deceleration states, (3) a reset signal output means for producing a reset signal if the outputs of all of said state changeover means are 1 and if said outputs of all of said state changeover means change from 1 to 0 thereafter, and (4) a lamp actuating means for turning said lamp on if the output of at least one of said state changeover means is 1 and turning said lamp off if there is a reset signal from said reset signal output means.