How to prevent radio power cut when starting

[laalves]

Hi,

I have a radio that, being Windows CE based, doesn't like to being fed with power when turning the key and immediately having cut off when the starter turns until it is permanently supplied with power after the engine is revving on its own. These false starts cause things like the iPod or the internal Bluetooth module not being recognised, requiring turning off and back on the radio.

Current work around is not forgetting to turn off the radio on its knob before taking the key out of the ignition, so that the next time I start the car the radio doesn't turn on. After the car is revving I then turn the radio on. But this requires me remembering the procedure, which doesn't always happen.

So, the question is, when I turn the key, which one is cutoff: permanent 12V or switched 12V or both? If it is the permanent 12V, then I guess I could just wire the radio directly to the fuse box, if it is the switched 12V, then it is more complicated to go around the issue.

[laalves]

Wow, no answer at all for 5 days already. Probably the first time this happened to me in this forum.

[Loren]

Does your car have phone prep (option M193/M553)?

If so, then you have the connector both switched and un-switched +12 volts, ground, and mute) under the center of the dash.

[Richard Hamilton]

Feed for the radio is Porsche Terminal 86s, which is ignition switched. It might be worth checking a Terminal 15 supply, which is also ignition switched. I have no idea if it will go off when cranking, but it is worth a try.

You don't say model or year of your car, but this is from the 2002 wiring diagrams which shows Bridge Plug 16/1 on the relay board, which is a Terminal 15 supply. Wire colour is Black/Brown.

[Loren]

Terminal 15 = switched +12 volts (only on when ignition is on)

Terminal 30 = un-switched +12 volts (always on)

Terminal 31 = ground

[laalves]

Thanks guys! Plenty of options to check in the car during this weekend.