Switched live ??

[SteveGTU]

A stupid question I'm sure but I'm putting my van back together and tonight I thought I'd just pop the old radio back in .
The live from the ignition switch only comes out at 6 v ? It goes in at 12v, the radio comes on for a few seconds when the van is starting then drops to 6v ?? Is this correct and if so where do I pick up my switched live??

 

[who?1]

The ignition switch should switch out at 12v I am sure so either the switch is not making correctly or a voltage regulator dropping the voltage to 6v is in the circuit.