Audio Systems: Amp install, car stereo wiring, stereo wiring diagram

Question
Hi Cleggsan, thanks in advance for any help. I have a 2002 ES300 with the Mark Levinson sound system. And the 8' subwoofer it came with is just not cutting it for me. I have a JL sub and an Alpine amp I'm going to install. I am going to use the sub signal for the HI pass signal. But I don't know what wire to use for the remote turn on for the amp. I have asked audio places and they suggest more equipment to buy. Which I will do as a last resort. I just know there's a way. Please help?

Answer
According to this the grey wire can be used to switch a sub amp on:

http://www.modifiedlife.com/2002-lexus-es300-car-stereo-wiring-diagram/

Also, you can do what I did on a Nissan Maxima which had a big subwoofer that I sometimes removed when I needed the space in the trunk.  I ran a wire from under the dash off the radio power and built a manual switch by my side on the drivers arm rest and back to the sub amp. It was really cool when a passenger was in the car with me and I switched the big subs on during the hot show off bass food music.  

Good Luck.