Tippmann A5 e-grip not working properly

Hello, I'm new to the sport, I've purchased a used A5 last year which came with the e-grip.  The seller demonstrated the marker for me with no barrel on or paint in and single fire as well as auto modes appeared to work, a few weeks later I got some air and paint and took it out to test it in a field before a match.  I wasn't able to get the marker to work at all and later found out from a local gun smith that he rest the grip to factory default (thinking the previous/original owner had messed up the programming) as it was operating in a test/trouble mode only.  I was happy to have it working but found out at the match that the marker would only fire a single round at a time; I tried everything I could think of to test the auto fire modes but nothing worked.  Over the winter season I did more research but I still haven't been able to get the auto fire modes working; I've opened the grip up to look for damage but the only thing I find strange is I'm not sure how the selector switch tells the board if it's in single fire mode or auto as there are no wires or connections.  Am I missing some piece in there?  The selector switch will only seem to allow the trigger to move or not move but there doesn't seem to be a differentiation between single and burst fire.