Marquette Battery Charger troubleshooting

I have a Marquette Fleet Battery Charger, Model 32-175 that appears to have no output at the battery clamps. Any ideas where I can find wiring diagrams or a troubleshooting ladder diagram? I just checked the output terminals (battery clamps) and when I turn the unit on, I have no voltage, however if I hold down the "dead battery" switch, I read 12.87 volts.
Author: jwallek