74 Dart Yellow Wire causing loss of Blower Motor and Radio?

On the original radio connector the red is the power and the orange is the light, no yellow.


Alan
I have add on gauge lights wired to orange, and the radio 12v power/gauge 12v power to the red. Everything works...but seems that if the underdash harness is repositioned I lose power to both the radio and the blower motor. I turned everything on and began tapping on ignition switch connector-- power went out. Began touching individual wire and it seemed there is a lose connection with the yellow wire from ignition switch connector.... I dont understand how they would be related...so most likely Im wrong but would that make any sense?