LiftMaster / Chamberlain1-1 when the LED state shows a connection/wire fault
The official 1-1 definition spans obstruction, misalignment, disconnection and wire breaks. LED state is required to decide whether the branch is beam-path or circuit-side.
Cross-brand failure family
Safety Sensor Wiring, Power & Hardware
Use this family when one or both photo-eye indicators are dark, the manufacturer reports shorted/reversed wiring, or the source/receiver is not being powered normally.
CROSS-BRAND QUICK ANSWERVerified September 2, 2026
A dark or abnormal sensor LED does not automatically mean the photo eye itself is bad. Chamberlain/LiftMaster and Genie both publish branches where wiring, terminal connections or power to the sensor circuit can produce the same no-close symptom. Verify the electrical path that the manufacturer exposes to the homeowner before buying a sensor pair.
Manufacturer signals
Same family, different language.
Do not translate one brand's blink count into another brand's code. Use the exact signal first, then the normalized family.
LiftMaster / Chamberlain1-2
Chamberlain Group documents reversed or shorted safety-sensor wiring for this diagnostic family.
LiftMaster / Chamberlainamber ON + green OFF / both LEDs OFF
The Chamberlain sensor LED table separates receiving-side wiring faults from conditions where both sensors are dark.
Genie Safe-T-Beamred OFF + green OFF
Genie lists an unpowered powerhead or bad wiring from the powerhead.
Genie Safe-T-Beam2 red blinks + green OFF
Genie lists missing/bad wire to the sensor or a defective sensor.
Genie Excelerator5 powerhead blinks
Excelerator five blinks identify a Safe-T-Beam malfunction broadly; dark or wiring-specific sensor LED states move the diagnosis into the circuit family.
Marantec EOS (M4500e/M4700e/M4900e)LED 7+8 → code 15
Verified M4500e/M4700e and M4900e tables map this display to photo-eye wiring/connection, alignment, or beam obstruction; a visible connection problem belongs in the circuit branch rather than a generic beam-only diagnosis.
Craftsman 139.53918D1 or 2 Learn-LED flashes
The exact Sears REV F chart uses one flash for an open/broken/disconnected safety-sensor circuit and two for shorted or reversed sensor wiring.
Check first
Low-risk discriminators
- Confirm the opener/powerhead itself has normal power before treating two dark sensor LEDs as failed sensors.
- Inspect accessible low-voltage wire for cuts, tight staples, loose terminal screws and exposed conductors touching each other.
- Use the sender/receiver LED combination to decide which side of the circuit deserves attention.
- Do not open a powered operator housing or bypass the reversing sensors to prove a theory.
Evidence against
What makes this family less consistent
- Both sensor LEDs are solid in the normal state and stay solid during the failed close attempt.
- A repeatable beam obstruction or misalignment visibly changes the receiving LED, which fits the beam-path family better.
- The door is mechanically heavy or binds with the opener disconnected.
Take the next diagnostic action.
Stop DIY here
- Wiring damage disappears into walls or requires mains-voltage work.
- The sensor housing, terminal block or opener electronics show burn damage.
- The sensor circuit will not return to the manufacturer's normal LED state after accessible wiring checks.