How will you reset the service light on a 97 Volvo 850?

To reset the service light on a 1997 Volvo 850, turn the ignition to the "ON" position without starting the engine. Press and hold the trip odometer reset button on the dashboard while turning the ignition off and then back to "ON." Continue holding the reset button until the service light goes off, then release it. Finally, turn off the ignition again to complete the reset process.