Installing amp and subs with the Infinity GOLD in Jeep

schectercsh1 · 05-02-2007, 12:05 PM

I have a 99 Jeep Grand Cherokee Laredo and I recently wired up a new headunit but unsure as to how I would go about wiring another amp in the back (keeping the stock infinity as well) and two subwoofers. If it's too big of a deal, I can remove the stock amp and just wire the headunit straight to the amp then to the subs, but I was wondering if anyone would know how to keep the stock amp in and add another?
Thanks.

UV7 · 05-02-2007, 01:12 PM

If you installed a new HU, then you should have everything you need to simply add another amp and subs. The existence of a factory amplifier is almost irrelevant.
First, you would need power and ground for the new amplifier. For a reasonably-powered sub setup, you are looking at a minimum of 4 guage wire from the battery to the amplifier, with an in-line fuse as close to the battery as possible. The keep the power circuit's current flow optimized, you need to use 4 gauge wire for the ground as well, keeping the ground wire as short as possible. Use a good, solid ground location, preferably a bolt or location that makes direct contact with the frame of the vehicle.
Next, you are going to need signal. Your new HU should have RCA outs on the back of it. If it is a fairly decent HU, it will most likely have a set specifically for a subwoofer. Generally, these RCA outs are not affected by the balance or fade functions of the HU. Simply run some decent RCAs to the new amplifier, keeping them as far away from the power and ground of the amplifier as possible.
Next, you will need a remote wire to tell the amplifier to turn on and off with the HU. Your new HU will already have this in place. It would have to in order to control the power of the factory amplifier. The wire color off the new HU should be Blue or Blue-White (Blue with a white stripe). Simply splice in a decent gauge wire, 18AWG is fine for remote, and then run it to the remote connection of the amp.
Last, you connect your sub(s). Be careful what you decide to use for subs, especially if you go with more than one. There are different wiring schemes involving multiple woofers that can dramatically affect the output capability of the amplifier and may even cause you to damage the amplifier and woofers.
If you have any questions, just let me know. Good luck and watch those volume levels! Neighbors usually don't like hearing your music in the middle of the night...er, at least mine don't!

schectercsh1 · 05-03-2007, 10:56 PM

Well first of all thank you, UV7, for the step-by-step process.
I actually just took the system out of my 84 vette, cause I'm re-building the car, so I figured I may as well put these things into my DD (jeep).
I suppose I might as well try wiring it normally without regard to the stock amp and see if it works, eh? My only concern is needing something like a capacitor, because of the uneven current from separate amplifyers (never wired two amps)
I'm using two phoenix gold xenon 10"s and an 1100 watt amplifyer.
My battery is old :/
Thanks!

UV7 · 05-04-2007, 08:30 AM

I highly recommend that you replace the battery if you are going to add multiple amplifiers. A capacitor is not going to resolve the problems created by a dying battery. As long as the new battery has plenty of amperage, you shouldn't need a capacitor. Check out Optima batteries.
You will, however, absolutely need a MINIMUM of 4 gauge wire for power and ground. You can branch off from distribution blocks to the two amplifiers with a smaller gauge power and ground to suit the amps' individual needs, but I would keep those stretches of lower gauge wire to an absolute minimum.
Good luck!