B4000 SE Regular Cab 4WD V6-4.0L OHV (1999)
Normal Operation
The air bag diagnostic monitor has the ability to deactivate the passenger-side air bag under certain conditions. When the passenger-side air bag is
deactivated, the passenger air bag deactivation (PAD) switch warning lamp will be illuminated.
The air bag diagnostic monitor monitors the PAD switch warning lamp for short to battery conditions. If the air bag diagnostic monitor detects a short to
battery condition on the PAD switch warning lamp circuit, it will store a diagnostic trouble code (DTC) B1890 in memory and flash a lamp fault code
(LFC) 27 (or higher priority code if one exists) on the air bag indicator.
Possible Causes
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A short to battery on (Y/LG) wire.
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A damaged or inoperative PAD switch.
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A damaged or inoperative air bag diagnostic monitor.