Curious as to how it tested good with a dead cell, the issue your experiencing is the fact that the battery isnt putting out 12v. lol What brand battery was it? If you havent gotten a replacement yet, I recommend a 26R, fits in the battery tray perfectly, but is shorter and not as wide, making it alot easier to get in and out when need be.

Just make sure if you buy one it has the terminals on the correct side.