my daylight flickers 5 times on and off then turns off completelt and then my service light soon comes on as soon as i put my car into reverse what causes it and what would stop and how do i fix it

The service light with a wrench symbol is a non emissions light. GM uses this light for oil change (based on oil condition) and headlight issues. The reset process once these are fixed is comical but easy to do. You need to (while car is off) pump gas 1 time & break 1 time; Then turn your key to the on (but not cranked) positions; pump the gas 3 times, press and hold the break 15 seconds; turn the car to off and then crank it and the reset is complete.