Door will not fully open; stops short of the usual open position.

Safety first: Keep clear of the door path while adjusting travel.

• Inspect header area: Check that the door arm and top section are not hitting the opener rail, header bracket, or ceiling.
• Adjust up limit: Increase the up travel limit on the Mighty Mule opener until the door reaches the fully open position without hitting stops.
• Check door balance: Manually lift the door. If it is heavy near the top, springs may be weak and should be serviced by a professional.
• Re-test: Run several open/close cycles to confirm consistent full opening.