Car Stereos: car stereos installation, bose amplifiers, amp trigger

Question
i have a 1999 Mazda millennia with a factory bose system.  I would like to install a aftermarket head unit i have all wiring harnesses to the radio. How can i get it to work i want to use my factory speakers. what can i do about the bose system

Answer
Hi Hayward,

The Bose system in your vehicle includes separate amplifiers attached to each speaker.  You can use them with the after-market head unit, but you'll need to do a little extra wiring and you may need to use a special adapter for best results.

If you have a wire harness that fits your vehicle's radio plug, you can just wire it up to your after-market radio harness like normal. However, you'll have to identify the amp trigger wire in the factory plug--my information is that it might not have a matching wire in the adapter harness.  The amplifier trigger wire should be light green with a red stripe, and it needs to be connected to the blue/white remote wire from your after-market head unit.  This will trigger the relay that turns on the Bose amplifiers.

The Bose amps should work with the output from the after-market head unit, but you may find that the volume is rather high--in other words, if the deck's volume setting goes up to 50, you might find that it gets extremely loud around level 10.  This is because the factory head unit produces a low-level signal for the amplifiers, and the after-market deck will be producing a higher level signal from the speaker outputs.  If this becomes a problem, then you can purchase a premium sound adapter to correct it.  A premium sound adapter is wired between the after-market deck's speaker outputs and the speaker connections in the wire harness, and it will include level adjustment dials to let you set a more reasonable volume level.  You can buy this part at any car audio shop.

Hope this helps!

Brian