im updating the stock sound system on my 1992 sc300. this is what i did so far:

1. im running 2 amps for mids/highs and bass

2. ran pwr cables from battery all the way to trunk via splitter with 30amp fuse

3. both amps are grounded to chassis in the trunk

4. alpine head unit: has 2 remote turn-on wires..........one is for antenna and other is for something else which i assumed it was for the amps to turn-on. there are solid blue and blue/white wires.
i used solid blue for antenna, and blue/white for my amps to turn on.

5. i used factory toyota harness which worked great and had my head unit to turn on and antenna workd
great also.

6. i ran all speaker wires to the trunk to my amps.

the problem? i cant seem to turn on my amps!

 

solid color is usually the turnon and the one with the stripe is usually antenna. Personally I just run a 12v constant as my amp turn-on wire through a relay but you can always just skip the relay part.

 

I think you should get yourself a voltmeter and check and see if the 12VDC power (REMOTE TURN ON) is coming on whenever you turn on your head unit.

 

As Retro said, blue is for amps and blue/white is for antenna. The way it works for the BLUE/WHITE is if you turn on your deck and press the tuner button the antenna rises or power is applied to this wire If you switch to CD player, antenna drops or power cuts from this wire. Where as the BLUE has constant power from the deck for amp remote turn on, amps will shutdown only if deck is powerd off. You were probably playing a CD at the time and that is probably why your amps are not coming on. Try switching the wires, or as Retro suggested have another wire provide remote turn on that is connected to ACC switched.