And two shall become one, and then two.
I have two five year old thunderbolt displays, One with no video and one with broken glass. I determined that the one with no display had a bad built in cable by plugging a thunderbolt cable into port on the back. When I found the teardown guide, I looke like a straighforward procedure. To test the bad cable theory, I removed the cable from the display with broken glass and installed it into the one with no video and it worked! I ordered the new cable and glass and put them into the other dipslay and both are now working perfectly, and as good as new.
The repair guide was very thorough and gave me all the information I needed. The first display went back together the first time with no issues. The second one had one of my ham fisted hand prints on the LCD behind the glass.
I thought the cable replacement would be the easy part but removing the glass is step 1. I can't beleive I lived with a display with broken glass for two years when it is literally a two minute fix. Removing the cable was a little more involved.