Discrepancy: Autobrake disarm light illuminates upon touchdown without crew applying brakes
Possible Fix: Brake pedal switch (S762 or S763)
Tip: To test for a possible short in the left or right brake pedal switches. Use a mulltimeter and check left and right brake pedal switches (S762 and S763) for continuity between pins 1 and 2 with brakes off. If there is continuity, replace defective switch. Tapping on the switch while testing may help locate intermittant switches.
Reason/Explanation: If one or both of the switches is shorted (has continuity without brakes applied). The Autobrake system assumes that the pilot is applying brakes and will disarm the autobrake system causing the disarm light to illuminate.
Applicable Reference:
WDM 32-42-11, 32-42-01
Thanks to Tom S. for his input !
