what happens if ABS brakes are replaced w/ non-ABS rotors? on 2003 Chevrolet S10

Recently helped a friend replace rotors & pads on an S-10 that had "non-ABS brakes". Only after installation he noticed the ABS light & brake lights on the dash were remaining on. What problems will this cause? Must the rotors be replaced with different rotors?

2 answers
I don't think this is related to the rotors, it's likely a sensor wire was left disconnected or something like that. Double check the work to see if this is the case.
There ARE different rotors for this truck for ABS or non-ABS. He must get the ABS rotors. These run between $40-$50 per rotor.