95 Nissan Quest HU harness 2 power amp?

I was installing a headunit for a 1995 Nissan Quest, to my surprise there was a build in factory amp. The amp is located in the rear left corner with car forward facing. The Metra guide indicated that the harness for this particular vehicle is 70-1770, but it’s only for a non-build in factory amps. Is there a harness for the build in factory amps so that I could wire it to an after market headunit? What I ended up doing was installing a FM modulator feeding the signal to the factory headunit and running the RCA from the new after market to the FM modulator. I wanted to wire the after market headunit directly to the factory build in amps so that I could get a better sound quality out of it. One look at the plugs on the back of the factory unit I didn’t want to process further. There are four plugs I had to content with, two large plugs roughly 8 pins, and I didn’t really count them and two smaller one. Any wiring diagram and instructions to tackle this problem is greatly appreciated. Thanks in advance guys. p.n.

Does it have the bose system in it?

I call several Nissan parts and service department a couple of minutes ago, but no one seems to know. I know that Ford is involve in making this van. This van is also similar to the Mercury Villager. Bose makes the highend stereo system for Ford and Nissan Maxima. I guess it's safe we can assume they make it for this one. p.n.

If it's a bose system it would say "Bose" on the front of the radio/display.

I didn't pay attention to the make at that time, I did what I knew. The customer wanted to keep the original factory unit in so I was kind of lucky that I got away with using a FM modulator. I may not be so lucky the next time and lose the business. Say it had a Bose or Infinity system. What's the trick to tackling this problem? Keeping it for future reference. Thanks.

To address your problem- chances are that if there were 4 plugs in the back of the radio, that only 2 of them were for the audio controls - whether it be a nissan harness or a ford premium harness - in any event, you can play into these factory amplified systems relatively easily. There are several signal output converters which can be wired in line with the audio ouputs on the deck that let you control the gains on each speaker so as not to overload the factory amp with the already amplified signal coming from the factory deck. The one that I use most commonly is manufactured by Install Edge and the model number is PSI2.

If it has the bose system you're supposed to use the FDAHW harness/adaptor.  All the connections can be made right up in the dash.

Thanks esmith69, That’s is exactly what I need! p.n.