I know this is an OLD thread but wondering where you found the broken ground wire. 99 Dodge Ram. I'm having the same issue, no light but 4x4 is working. Replaced the switch, jumpered the wires, still no light. Seeing 13 volts at the switch. Thanks.
I have no real idea what the ground issue discussed here was. I have either a '98 or '01 service manual uploaded to 4Share. I would guess the '98 is closer to the wiring diagrams you need. If you'd like a copy and maybe some help tracing it out, send me a PM.