Usually tiny hands can gain acess in front on the batter to replace bulbs! But if you reset your ECU, your pretty much let your computer on a learning curve. More your drive and what type of fuel you put equates the power you receive. If you want to re-reset it, just diconnect the negative terminal from the batter for 5 minutes and reconnect (do note if by re-reset you mean going back to you original settings, its not possible).