garage door -new thread

Thanks for earlier responses. The title "Garage door" seems to have been used a lot so I'm trying to retitle to avoid excessively long thread.
The hardwired button works if held in. The yellow light on the back (1/2HP Craftsman) flashes 2 every few seconds. The sensors have no lights. I disconnect the green light sensors and wired it directly to the back of the unit. If working correctly, I should see a light but since not lined up, it should flash. I see no light. I'm convinced either the main box has a logic board failure of the sensors are bad. Is there anyway to determine where the problem might lie without trial/error? Also, if parts of the unit need to be replaced, would it be better just to replace all? The unit is approx. 5 years old.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.