Troubleshooting Diagnostic Chart - Chamberlain LiftMaster 8500C Mode D'emploi

Troubleshooting
Diagnostic Chart
Your garage door opener is programmed with self-diagnostic
capabilities. The diagnostic LED will flash a number of times, then
pause, signifying it has found a potential issue.
Consult Diagnostic Chart below.
1 FLASH
Safety reversing sensors wire open
(broken or disconnected)
OR
2 FLASHES
Safety reversing sensors wire shorted or
black/white wire reversed
Installed
Safety Reversing
3 FLASHES
Sensor
Door control or wire shorted
4 FLASHES
Safety reversing sensors slightly
misaligned (dim or flashing LED)
5 FLASHES
Motor RPM is not recognized
9 FLASHES
Cable tension monitor reversal
10 FLASHES
Limits and forces need reprogramming
11 FLASHES
Limits and forces need reprogramming
12 FLASHES
Installed
Attempting to compensate
Safety Reversing
Sensor
13 FLASHES
Attempting to compensate
Installed
Installed
Safety Reversing Safety Reversing
Sensor
Sensor
SYMPTOM: One or both of the Indicator lights on the safety sensors do not glow
steady.
• Inspect sensor wires for a short (staple in wire), correct wiring polarity (black/white
wires reversed), broken or disconnected wires, replace/attach as needed.
• Disconnect all wires from back of garage door opener.
• Remove sensors from brackets and shorten sensor wires to 1-2 ft. (30-60 cm) from
back each of sensor.
• Reattach sending sensor to garage door opener using shortened wires. If sending
sensor indicator light glows steadily, attach the receiving sensor.
• Align sensors. If the indicator lights glow, replace the wires for the sensors. If the
sensor indicator lights do not light, replace the safety reversing sensors.
SYMPTOM: The door doesn't activate from the door control.
• Inspect door control/wires for a short (staple in wire), replace as needed.
• Disconnect wires at door control, touch wires together. If garage door opener
activates, replace door control.
• If garage door opener does not activate, disconnect door control wires from garage
door opener. Momentarily short across red and white terminals with jumper wire. If
garage door opener activates, replace door control wires.
SYMPTOM: Sending indicator light glows steadily, receiving indicator light is dim or
flashing.
• Realign receiving sensor, clean lens and secure brackets.
• Verify door track is firmly secured to wall and does not move.
SYMPTOM: Door travels 2-3 inches and stops.
• Reprogram limits and forces. See Adjustment section.
• If the motor unit continues to travel 2-3 inches, check the travel module connection
or replace the travel module.
SYMPTOM: No movement, motor runs 2-3 seconds.
• Reconnect the emergency release.
• Motor may need to be replaced.
SYMPTOM: Door stops and reverses while closing.
• Check for possible door obstructions and remove.
• Check that the cable tension monitor is properly connected to the opener.
• Replace the cable tension monitor.
SYMPTOM: Door stops while opening.
• Reprogram limits and forces. See Adjustment section.
SYMPTOM: Door stops and reverses while closing.
• Reprogram limits and forces. See Adjustment section.
SYMPTOM: Door stops and reverses while closing.
• Garage door opener will try to compensate three times before turning to a 10 Flash.
SYMPTOM: Door stops while opening.
• Garage door opener will try to compensate three times before turning to a 11 Flash.
30
Garage Door Opener
Diagnostic
LED
Safety Reversing Sensor