Wire tap for connecting a subwoofer amp

On the Prius III, there is a factory JBL system with 6 disc CD changer and 8 speakers: four woofers and four mid-high range.

I decided to tap the amplifier under the passenger seat for another amplifier (alpine mono-block 300W @ 4ohms, 500W@ 2 ohms RMS) to power my single Alpine Type R 10" @2 ohms.

There is a plastic cover that is held in place with two plastic retainers. Use a flat head screwdriver to pry up the center lock pegs and the retainers come out. There are three different sets of wiring harnesses. I believe, from left to right, the first (white) wire harness is for the mid to high frequency range (output). The next wire harness (blue) is the low frequency output. The third (white) wire harness has very small gauge wires, and I beleive it is the input.

I tapped four wires from the blue harness for speaker level input to the Sub Amp: Red (RR+), White (RR-), Black (LR+), and Yellow (LR-).

Do NOT tap the first wire harness for low frequency output.

I found that the light blue wire on the first harness serves well for a remote wire tap... I am not sure if that is it's function, but it turns the AMP on whenever the car is on any setting other than off.

I hope this helps anyone who wants to add more bass to an already superior system and doesn't want to pay the geek squad 75 dollars to hook it up .

 

LOL, yes.. that was the easy part as the battery terminal and a clean ground is right there in the back, where I installed the amp. I didn't tap the power, I am using an 8 gauge wire to the battery and a 12 gauge to the ground screw connected directly to chassis.

However, I have ran into a problem... my 10" driver keeps cutting out at high volume (say, anything over 34 on the JBL radio). I think the cause is related to the fact I tapped amplified wires... I should have tapped the input to the JBL amp, but I didn't have that information. I see another thread on here that may ahelp with that.
thanks!