'97 DS Won't Move

[hclancaster]

I have a '97 DS Powerdrive Plus (SN A9739-608955). The other day, the cart stopped going at all, in either forward or reverse. No solenoids click. The batteries charge OK and read 50V. I confirm that the key switch works. The FWD-REV toggle switch works and operates the buzzer. I see 50V at the first of 2 solenoids (red wire), and I measure 47 V on yellow wire out. What's a next step in troubleshooting this? Is the a way to activate 1 or both of the solenoids? (What doeach of them do?). Thanks!