Hi l have a 1989 Volvo 240 DL and it has a reset switch on the back of the gauge cluster?. What is it for and how do l work it.

 

that's for service light reset

 

Thank you for the information about the reset switch. I have another problem with the speedo being out by 30km hr. I checked the gear in the cluster and it has no missing teeth. This problem happen when l changed a bulb in the cluster, before that it worked fine.?

 

try tighten all the screws @ the back of the instrument cluster & the bulbs first, inspect if the mother board if any broken