sold horse,bought ss

ok I was racing my 98 ss with the factory 4 channel 7.5 last night when this happened. I made 4 passes on radials and after the 4th my dash lights came on and have stayed on. someone said it may have been because my radials are a different size than my factory tire but I had raced it 2 weeks ago and made about 12 passes with no problems on the same radials. any suggestions or a way to reset the system? thanks for the help