Protection control box for the M809 series of 5ton trucks (M813, M816, M817, M818, etc). P/N WSU4001UT, WSI4001UT, 11664348. NSN 2920004721642. Made in USA.
This control box provides reverse polarity protection, electrical spike protection, controls DC power to accessory circuits, controls/protects alternator output (60 amp alternators only), controls power to starter motor solenoid, locks out start circuit when engine is running (sensing by oil pressure switch).
Control box will be damaged if the vehicle’s engine is not shut down properly. Turn off ignition switch first. Wait until engine rotation completely stops. Then turn off battery switch.
Damage from improper shutdown is not covered under warranty.
Box must be grounded via mounting bolts to operate properly.
Do not use this control box on the M939 series.
No export from USA.