Chamberlain Garage Opener Blink 4-5 — Quick-Close Fault

What Does This Error Mean?

Blink 4-5 relates to the quick-close feature — the opener's option to automatically close the door faster than normal during certain conditions.
The fault means the controller can't safely engage the feature, usually because the photo eyes are obstructed or misaligned.
Check that the safety beams have a clear line of sight, then run a normal close cycle.
Most cases clear once the photo eyes are aligned.

Affected Models

Chamberlain B970
Chamberlain B1381
Chamberlain RJO70
Chamberlain B6753T
Chamberlain belt-drive openers

Common Causes

Photo eye sensors misaligned
Photo eye lens dirty or cobwebbed
Sun directly on a photo eye lens (false beam break)
Photo eye wiring damaged
Quick-close feature firmware issue

How to Fix It

Inspect the photo eye sensors.

Look at the two sensors on either side of the garage door, mounted near the floor.
Each has an LED that should glow steady.
If either is off or flashing, that's your blink 4-5 source.
Misalignment is the most common cause.
Realign the sensors.

Loosen the wing nut on each sensor bracket.
Adjust until both LEDs glow solid green or amber (depending on model).
Tighten the wing nuts.
Don't overtighten — the brackets are flexible plastic and crack under force.
Clean the lenses.

Wipe each photo eye lens with a soft dry cloth.
Cobwebs, dust, or condensation can block the beam.
For dried-on dirt, use a slightly damp cloth then dry immediately.
The lens is small — a cotton swab works well.
Check for sun glare.

If your garage faces west or east, direct sun can shine into one of the photo eyes during certain times of day.
The opener interprets the bright light as the beam being broken.
Add a sun shield (a small cardboard or metal flap) above the affected sensor.
Run a manual close cycle.

After fixing alignment and cleanliness, press the down button on the wall control.
The door should close cleanly without pause or reversal.
If blink 4-5 returns, the photo eye system is still seeing an issue — recheck wiring or replace a failed sensor (15–30 USD).

Frequently Asked Questions

Can I disable the quick-close feature?

Yes — most Chamberlain models have a setting (often called 'time-to-close' or 'auto-close timer') that can be disabled from the wall control or app.
Disabling it means the door only closes when you tell it to, no automatic closes.
Worth doing if blink 4-5 keeps appearing.

Why is the LED on the sensor flickering?

Flickering usually means a marginal alignment — beam catches the receiver intermittently as someone walks past or as the brackets shift in vibration.
Tighten the brackets and re-align until the LED is rock-steady solid.
Flickering reliably becomes blink 4-5 over time.