Hilti TE 5 locking up when put in hammer drill mode

i took apart my Hilti TE 5 to clean it up a little and put it back together. Everything seemed ok no issues or anything but then when I moved the switch to the hammer drill mode it just makes noise but doesn’t spin or anything like it’s locked up but in the drill mode it works just when switched to hammer mode, it’s locking up for some reason. Any thoughts on what might be wrong or why it’s doing this?