MEX-BT3900U Car CD Radio ON/OFF function

[dal5band]

Can the Sony car radio be switched ON, even with the car ignition off ?  I cannot get my BT3900U to come on when I press the source/off button if the ignition is off.  With the ignition on, the unit can be swithed off and on normally. I have checked the wiring - yellow lead is always on and the red lead comes on with the ignition - this is the correct wiring in accordance with the installation sheet. I am sure the is power is ON as the radio beeps and memory is not lost.

Thanks

Message was edited by: dal5band

Message was edited by: dal5band

[Drumzman · Accepted solution]

Hi dal5band,

This usually depends more on the car than the radio - some vehicles will continue to supply power through the switched supply (red lead) if you turn the ignition key all the way to the off position (although often the key has to remain in the ignition).

For what's it's worth you have definitely wired your unit up correctly and everything you describe sounds like normal operation.  The only way you could get your unit to switch on and off independently of the ignition is to wire both the red and yellow wire to the same 'always on' supply in your car  This is a perfectly legitimate alternative way of connecting a car stereo, but the disadvantage is that the unit would then not automatically switch on or off with the ignition.  (It means that you have to remember to manually switch off the unit when you leave the car - there's always that risk that you forget if the volume was down for example, and the risk of a flat battery, especially as winter sets in!)

Hope this helps.