Display shows E12; opener may run only in one direction or not at all.

Safety: Disconnect power before opening the operator housing.

• 1. Test both directions: With the door disconnected, command the opener to open and close. Note if one direction fails consistently.
• 2. Listen for relay click: When commanding movement, listen at the opener for relay clicks. No click in one direction suggests a board fault.
• 3. Inspect board for damage: Look for burn marks near the motor output terminals or relays. If present, the board must be replaced.
• 4. Check motor carriage resistance: With power off and carriage disconnected, measure motor winding resistance (per Sommer specs if available). A shorted motor can cause E12 and will require carriage replacement.
• 5. Replace failed component: Replace the control board if the output stage is damaged; replace the motor carriage if the motor windings are shorted.