So I made a big mistake and ended up ordering my new headunit from best buy instead of Crutchfield... My main goal was to get a touchscreen display with apple car play so I can have navigation/ easy access to all of my music- the JBL system was adequate for me as far as sound goes.



Long story short, the PAC interface they gave me does NOT have an adaptor for the factory JBL amp, and I ended up losing power to the amp and destroying the sound quality. I no longer have sound coming from my stock subwoofer or front center speaker, and the rest of the speakers start clipping at about 1/3 volume (even after fiddling with the gain on te interface quite a bit). Im pissed at best buy because I asked a dozen times if it would work with the factory amp but of course, it did not.



Basically I have a few options-



1. buy the correct harness from crutchfield. This may be my best bet because I'll get back the sub and front center speaker, but im not sure if I'll still get better results by replacing door speakers with aftermarket components.



2. Replace the front and rear door speakers and keep the rest as is. Has anyone replaced the front and read door speakers without replacing the stock speaker wiring? I really dont want to pull all of my trim in order to run new wires, so this is likely the decision maker for me. If I go this route, I imagine the aftermarket 6"x9" in the front doors will give me a solid upgrade in the bass department, but may or may not be as good as if the stock 8" in the back was still working.

3. Somehow activate the factory amp without the harness? Is anyone aware of a way to hotwire the amp harness to get it to turn on? I saw on a forum somewhere that the factory harness contains a few data and a remote wire. Can i connect the remote wire somewhere to get the factory amp to turn on and solve my horrible sound issues?

You're going to need to get the correct radio interface regardless of what you do with the speakers. I'd do that first and see what you think before worrying about speaker upgrades.

The JBL systems only pass digital signals between the factory head unit and the amp in the back. All processing (volume/bass/treble/surround/fade/etc.) are actually done in the amp. The head just sends commands telling the amp what to do with the audio data. So, you need the correct JBL interface (PAC/Crux/whoever) to convert your aftermarket unit's analog signal output into the digital signals the JBL amp needs.

Some of the interfaces available work from the preamp output on aftermarket units, others work from speaker level outputs. One thing they'll have in common is you need to choose some specific settings on the *factory* head before removing it. Like set volume to max, set bass/mid/treble to 0, balance/fade to 0, and your preference for surround on/off.

Good luck.

One other thought. If they botched it this badly by doing some sort of half-assed amp bypass (or feeding the speaker outputs directly into the JBL amp), they probably didn't get your antenna connections correct, either. The 4Runner has a signal amplifier on the antenna input so your aftermarket head needs to have the appropriate turn-on wire connected to trigger power to the antenna amp or you'll get very poor radio reception.

To really do it right, there's a Y-adapter available that can combine both of the 4Runner's antennas into one connector that fits the single antenna input common on most heads. I think it's technically a Delco part, but search should find it easily enough. The 4Runner uses a diversity setup with antennas in both rear cargo side windows...the factory head then constantly compares the signal received at each antenna and uses the better of the two. Depending on your proximity to the radio station transmitter, your reception could suffer by losing the diversity feature.