Loose connection on handle trigger.
1. Remove the two screws holding the cover in place on the backside of the trigger. Once screws are out push on the trigger inward forcing the cover to push out. Remove cover.
2. Check to se if wire terminals are loose by wiggling and pulling gently
3. If terminal is loose in back of switch use a pair of pliers to put a bend in the middle.
4. place terminals back into same connection. make sure all connections have good contact. terminals should be firmly in place.