I have searched the forums using various search terms and although I have found some information explaining switchable power for things like accessory adaptors I still feel a bit in the dark as far as the wiring procedure for installing a new head unit in my 04 MC.

I realize I can call Crutchfield for directions but I thought it might benefit everyone here if there was an explantion thread on the site for those of us that are inexperienced when it comes to the electrical side of a motor vehicle.

If someone would be so kind as to explain in layman terms the difference between a switchable power source and a constant power source that would be a great start.

As well, how do you wire an aftermarket head unit to switchable power and constant power in a Mini Cooper?

Any and all help is appreciated.

 

I'm no guru, but essentially constant power is there for your radio's memory- i.e. memorized radio stations. The switchable power is to automatically turn the radio on when the car is in 'accessory' mode. The MINI also provides power on demand even with the key off, for a predetermined 20 minute interval, so you don't wear out your battery.

Here are the pinouts for the head unit. You can get wiring loom adapters cheap on ebay so you don't have to hack up the OEM harness.