My starter has three wires, how do I hook it up. on 1994 GMC Suburban 2500

Have changed the starter and fly wheel. Think I have starter hooked up wrong. It has three wires. Also, when hook up batteries to try to start, batteries spark and Glow plug stays on all time. Think I might have starter connected wrong

Asked by for the 1994 GMC Suburban 2500
you have large cable which hooks to large terminal thats easy, the starter hit wire goes to small terminal on solenoid on start side.the solenoid should be marked i for ignition and the other wire goes to the other terminal marked r for run. hope this helps