How do you turn off a 1987 Volvo 240 service light?

To turn off the service light on a 1987 Volvo 240, you need to reset the maintenance reminder system. Start by turning the ignition to the "on" position without starting the engine. Then, press and hold the trip odometer reset button until the service light turns off, usually within a few seconds. Release the button, and the light should remain off when you start the vehicle next.