Not sure how, but I think I got it wrong. I removed the red cable connected to the (+) terminal, cleaned it up, an tested for continuity from it to the frame; nothing, no connection. Then did the same test on the black cable; dead short, as it should be. Tracing the cables, the red cable connects to a contactor and the black cable is bolted directly to the frame.
Last night, while doing quick tests, I just checked for continuity from the battery (+) to the frame and got a beep from the meter. Same check on the (-) battery terminal gave no beep. Maybe the battery is shorted and I got continuity from (+), through the battery, through the black cable, and then to frame. Then, when testing the black cable, didn't have good contact on the meter probe??
All very strange. Maybe all I need to do is install the correct battery. Does this one from Walmart look OK?
BTW-thanks for the help!