Volvo Repair: Service Light, instrument cluster, unleaded gas

Question
1989, Volvo 740GL, Service Light came on. I changed the spark plugs, oil, oil filter and so on. The light is on when I start the car but  goes out about 6-7 mintues later. How can I turn it off until next time.

Answer
Terrence, the 89 should have a button that is covered with a grommet on the instrument cluster.  If not, then you have to pull the instrument cluster out and feel for the reset button behind the cluster.  Remove the small covers.  One will say unleaded gas.  There are 2 screws behind there.  Remove them and carefully remove the cluster.  Roger