I have a 96 Dodge Ram SLT , the High-mount brake is equipment with a Cargo lamp and when I turn the **** all the way to Cargo the light fails to turn on. I took a multimeter to the wiring harness at the high-mount on the plug and the got no continuity. Could any help me figure out where to go next and which prongs go to the cargo light on the dash switch.

 

You should be measuring for voltage to see if power is being sent to the connector. Did you check the bulb and the fuse?

 

No voltage at the plug to the Cargo lamp wires on the truck side.

 

Fuse, bulb?

 

Fuse good, Bulb good.

 

Which fuse did you check? Manual says IOD Fuse 17 is hot at all times.
Make sure there is voltage at the fuse.
Ground to the lamps is provided by the switch.
Check for zero ohms to ground at the lamp socket with the switch on.

 

Ok, if the dome lamp, visor lamps. and ignition switch halo lamp work, you should have voltage to one side of the lamps.
The switched ground side connects to connector C206 pin 6 at the switch on a pink with a dark blue stripe wire.

 

Any progress?

 

Not yet, I've been busy with a couple other projects