Yellow LED on Nybble Board won't light up

I've been working with the Nybble kit on college vacations since the most recent holiday break and I've had to resolder the pin connectors for the ultrasonic sensor at least 4 times due to my own lack of carefulness. Recently I put in the batteries for the first time since at least March and I found out the yellow LED (the cat's right eye on the board) won't light up-- I hooked it up to a Voltmeter and no electricity is going through it. I don't remember if it ever lit up in the first place, but is there the possibility that soldering the pin connectors for the ultrasonic sensor or the connectors for the Raspberry Pi screwed up the part of the circuit that gets voltage to the left LED? If so, is there anyway to fix it or do I need a replacement board? Could anything else be affected or just the LED which is seemingly there for aesthetic? This has been my first major electronics kit so I don't even know if these questions can even be answered without further inspection of the board.