Ignition Switch Question

[CRGRS 66]

I have a 66C10. The ignition switch has three positions (not including the engine start sprung position). So off obviously, then the mystery position, and run. Is the position between off and run an accessory position? Sometimes I would like to run my radio with the engine off, but don't want to have the ignition on and cook the points etc. I have tried using a test light to see if there is power on any of the leads on the back of the ignition switch when the key is in this position, but no lighty upy!