I want to bypass the existing AMP and run the outputs from the head unit straight to a new high powered amp that I am mounting behind the rear seat. Anyone know how the wires are laid out from the head unit? Or is there an aftermarket harness available anywhere?

It uses the same harness that most Hondas have used since about 1998. If you need a pin-out let me know and I'll post one.

I think the amp is in the head unit?

The amp is in the head unit. The output is speaker level.

There is one set of preouts available on the 14 pin connector. This has been discussed ad nauseum in a host of other threads. Your best bet, if you want to keep the head unit, is to use an amp with speaker level inputs.

Your best bet, if you want to keep the head unit, is to use an amp with speaker level inputs.
I wanted to keep the factory head unit om my last vehicle so I put in an EQL to convert the speaker level audio to low level and than ran it to an amp. It sounded pretty good, I also replaced all the speakers with MB Quartz. I am looking at at the very least replacing the speakers in my Ridgeline.

YES!!!!!!!!!!!!! djdj, please post the pin-out diagram. That will clarify most of the talk and anomolies that have gone on around this discussion. At least for me it will.

Thanks.

Dave