JD 3010D Starter/Ignition Switch

[MinnesotaGuy84]

I recently purchased a John Deere 3010 Diesel that had been sitting for several years. It is a 24 volt system. I have replaced the voltage regulator, solenoid and batteries. Also, I have had both the generator and the starter rebuilt. It doesn't want to start now. When I crank the engine it doesn't crank very hard and when I back the key off to the "off" position it keeps cranking, but at a much slower rate. I then have to disconneect the battery. So it seems to me that if the starter doesn't stop cranking the current must not be cutting off at the switch. How do I test the switch? I have a multimeter with an ohms setting. Currently, I get continuity when I test between ST and BATA, but the continuity does shut off when I turn the switch off. However, I don't get continuity between ST and BATB when I turn the key. Can someone please help me make sense of this?

Thanks