Chamberlain CG40DM 2. My remotes will not activate the door:, 5. My lights will not turn off when door is open:

HAVING A PROBLEM?

1. My door will not close and the light bulbs blink on	Bell Wire
my motor unit: The safety reversing sensor must be
connected and aligned correctly before the garage door
opener will move in the down direction.
• Verify the safety sensors are properly installed,		1 2 3
aligned and free of any obstructions. Refer to
Installation Step 10: Install The Protector System ®.
• Check diagnostic LED for ﬂashes on the motor unit
then refer to the Diagnostic Chart on the following		1
then refer to the Diagnostic Chart on the following		“Learn”
page.		“Learn”
page.		Button
		Button
		LED or
2. My remotes will not activate the door:		Diagnostic
2. My remotes will not activate the door:		LED
• Reprogram remotes following the programming	Safety Reversing Sensor	LED
• Reprogram remotes following the programming	Safety Reversing Sensor
instructions. Refer to Programming.
• If remote will still not activate your door, check	Sending Eye Safety	Receiving Eye Safety
diagnostic LED for ﬂashes on motor unit then refer	Sending Eye Safety	Receiving Eye Safety
diagnostic LED for ﬂashes on motor unit then refer	Reversing Sensor	Reversing Sensor
to Diagnostic Chart on the following page.	Reversing Sensor	Reversing Sensor
to Diagnostic Chart on the following page.	(Amber Indicator Light)	(Green Indicator Light)
	(Amber Indicator Light)	(Green Indicator Light)
3. My door reverses for no apparent reason: Repeat
safety reverse test after adjustments to force or travel
limits. The need for occasional adjustment for the force
and limit settings is normal. Weather conditions in
particular can affect door travel.
• Manually check door for balance or any binding
problems.
• Refer to Adjustment Step 2, Adjust the Force.
4. My door reverses for no apparent reason after fully	6. My motor unit hums brieﬂy:
closing and touching the ﬂoor: Repeat safety reverse	6. My motor unit hums brieﬂy:
closing and touching the ﬂoor: Repeat safety reverse	• First verify that the trolley is against the stop bolt.
test after adjustments to force or travel limits. The	• First verify that the trolley is against the stop bolt.
test after adjustments to force or travel limits. The	• Release the door from the opener by pulling the
need for occasional adjustment for the force and limit	• Release the door from the opener by pulling the
settings is normal. Weather conditions in particular	Emergency Release Rope.
can affect door travel.	• Manually bring the door to a closed position.
• Refer to Adjustment Step 1, Adjust the UP and	• Loosen the chain by adjusting the outer nut 4 to 5
DOWN Travel Limits. Decrease down travel by	turns. This relieves the tension.
turning down limit adjustment screw clockwise.	• Run the motor unit from the remote control or door
	• Run the motor unit from the remote control or door
	control. The trolley should travel towards the door
5. My lights will not turn off when door is open:	and stop. If the trolley re-engages with the door, pull
• The garage door opener is equipped with a security	the Emergency Release Rope to disengage.
• The garage door opener is equipped with a security	• Decrease the UP travel by turning the UP Travel
light feature. This feature activates the light on when	• Decrease the UP travel by turning the UP Travel
the safety sensor beam has been obstructed.	adjustment screw 2 full turns away from the arrow.

• Re-tighten the outer nut so the chain is a 1/4"

(6 mm) above the base of the rail. (When the door is reconnected and closed, the chain will sag. This is normal.)

• If the trolley does not move away from the bolt, repeat the steps above.