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3. Drive motor works in forward mode but does not reverse, blower motor runs.
A. If computer dot (second one from left) does not come on, check program to see if set for reverse.
B. If set for reverse, replace computer.
C. Check for voltage across the coil of the reversing contactor located in the rear panel box. The
contactor according to your diagram is CR3, also the markings on the coil are A1 and A2.
If there is voltage replace the coil or the complete contactor.
If there is no voltage, check for voltage across the two BS1 terminals on the arc suppressor board.
If there is voltage across the two BS1 terminals and no voltage across the coil of the reversing
contactor (A1 and A2), the problem is bad wire(s) or termination(s) between BS1 and the contactor
coil.
D. If there is no voltage between the two BS1 terminals on the arc suppressor board, check for voltage
across the two AS1 terminals on the board.
If there is voltage across the two AS1 terminals and no voltage across the two BS1 terminals, replace
the arc suppressor board.
If there is no voltage across the two AS1 terminals, the problem is bad wire(s) or termination(s)
between the arc suppressor board and the computer 15 pin connector no. 8, or a faulty computer.