My service light was always hard to push in over the years but this time around my service light stays on after I push it in on my 1991 240 wagon. I thought the light was a reminder to change the oil every 3K. Since I do it every 5K, I always ignore and push the pin in untill now. Does the service light need to be reset somewhere else? (test box in the engine). Appreciate any tips! Black tape over the light may be the next step unless the car is trying to tell me something serious. Thanks!