Most likely a short under the rubber boot of one or more of the connectors. The insulation gets crispy and it chips off right where the wiring enters the connector. Gently cut off the rubber-boot with a razor. It's glued to the wire & connector and trying to pull it off will break the rest of the wiring.
Inspect each connector where the wire goes into the connector. See if one of the connectors has its bare wires shorted across to each other. Separate the shorted wires and re-measure the voltage on each terminal.
Might as well replace all the connectors. I cut them off 6" from the end and butt-solder new ones on from NAPA. Two styles available:
NAPA - CRB 218457 (new style with finger-operated spring)
NAPA - CRB 218545 (original style)
