rx7duck

So, I've been trying to figure out how the main harness (J-11) to the headrest speaker amp works so I can use the headrest speakers and center console switches when I replace the head unit with an MP3 headunit. Most of it was pretty easy but I could not for the life of me figure out the left/right and polarity of the signal inputs into the headrest amplifier to figure out how to hook it up to the new head unit.

After lots of lots of surfing, I found a pin layout for 1990 Miata headrest speakers similar to the J-02 harness which I THINK gave me the information I was looking for.

I've also read from my searches here that the headrest amp doesn't get enough juice from pre-amp signals and starts popping if you exceed 15W. So I plan to power all four front speakers off of the front output of the new head unit and connect the head unit rear outputs to the headrest speaker amp. In theory , if I keep that faded fairly low, I can fine tune it so the headrest amp gets enough, but not too much, signal.

So, here's my decode of the J-12 harness:

LG/Y: Dirver right speaker +
L/B: Driver right speaker –
LG: Driver left speaker +
L/Y: Driver left speaker –
L: Right signal in +
L/O: Right signal –
BR: Left signal in +
BR/W: Left signal –
L/W: Switched power from ignition
BR/R: Not sure on this one (I have two guesses: Either it tells the head unit to do surround or it’s switched power from the head unit to the headrest amp – I’m guessing it’s the latter and will test when I get around to doing the install)
B/R: Ground
G/R & G: Volume up from center console switches
G/Y & G/W: Volume down from center console switches
Y: Surround on/off from center console
L/R: Unswitched power in
LG/B: Power out to console switches
LG/R: Headrest speaker power from center console switch
BR/B: Ground to center console switches

FYI: The passenger headrest speakers connect using the J-12 connector.

Posting this here in case anyone else might find it helpful in trying to redo their stereo and still retain all of the headrest speaker functionality.

Icemark

Icemark

rx7duck

Yes, that's very similar to the one I was using. (from 1990 manual) but it still doesn't tell you what the wires between the head unit and headrest amp are for. ( Blue, Blue/Orange, Brown, Brown/White, Brown/Red) Is there something that decodes the letters there on that diagram to tell you what the wires do?

Ronin Rotary

blue, blu/Org , brown, Bwn/Wht are speaker output colors for the rear speakers. so in a system with a headrest speaker, they are the high level output from the headunit with the signal to the amp.