My ranger 2900 goes of if it falls forward on bracket what can this be

Sounds exactly like you don’t have a good ground or power connection, it may be possible that the wire connector has a lose contact to the main board where it is soldered from the wire to the board but I think you have a lose connection first before digging into it. Add a bonding wire (ground) from the unit to the vehicle bypassing the hanger bracket and its ground as it is screwed to the vehicle, the more grounds the better.