If it is blinking rapidly it is receiving a signal. If it is blinking randomly it is normal.

It blinks 5 times stops for 3 secs and blinks 5 times again. Pushing the open/close button on the wall controller gives us a clicking sound, but no response. Using the remote doesn't produce even a clicking sound. Apparently it's not recieving a signal? We have 2 door openers so I saw what you meant about blinking randomly / recieving signal. Thanks for your quick response and help!

Oops I gave you the wrong information. The code that LED is sending is "RPM sensor or motor overload." Mos commonly when this happens the door has traveled too far in the up direction and the trolley has jammed against the bolt just in front of the motor housing. If this is the case you can loosen the chain until the stress is removed from the chain and then the motor should run the door down. While the door is down locate the 'up limit' on the side of the motor unit and turn the control 2 full turns in the opposite direction of the arrow printed on the cover. Now tighten the chain.

Thanks for that info, it gaves us more to go on in diagnosing our problem.
The chain is clear. We noticed while checking the chain an electical buzzing sound when you touch or tap the black box on the opposite side of the limit switches. Also, light bulbs will not come on. Any ideas?

Is the "black box" you refer to a round cylinder about 5 inches long with 4 wires going to it?

No, it's square with bottom right corner missing. It says DANGER and has 2 diagrams I think showing "how to" and "how NOT to" open the unit safely. It says not to use higher than 75 watt bulb and has a triangle with an electric bolt in it.