Add Rear/Headrest Speakers to your Miata
Note: these speaker connections are the same for all standard Mazda radios - the cable kits available on eBay for a few dollars include a rear/headrest speaker plug with cable as well as a main cable plug and cable. Of course I didn't figure this out until after I had done it the hard way.
I wanted to add rear speakers to my '00 and having dug thru way too much information about radios, mostly misleading because they were written about pre-'99 cars, I deceided to document what I found out. Not to flame Miata Net or other Web pages, but you guys need to get real and realize that Miata production didn't stop in '97 and all articles should be updated to reflect the model year it applies to. With that said, here goes.
OK, for all the '99 & '00 owners with an 4M32 radio/CD player, (the 4M32 is printed on the top rigth front corner of the radio) here's what's really available on the back of the unit.
There are 4 connectors and a ground spade. There is a standard antenna connector, a connector for the optional tape deck, the main connector and next to it is a headset connector. The 4M32 does indeed have a FADER control when you press the AUDIO button, but no factory installed cable or wiring. There is no 2/4 or rear speaker switch anywhere on the radio, the fader feature is already enabled. A base '00 will only have things plugged into the main connector, the antenna plug and the ground spade. The pinouts on the "Miata Net Garage " are correct except there is no round DIN plug on a 4M32. That article is talking about a Panasonic unit and the '00 has an FMS radio, but what he called the MAIN Conn. and the HEADREST Conn. have the same pinouts, however there is no numbering or lettering of the pins on the FMS radio. Use the picture to connect your wires.
The radio slides out the front without removing the console, eyeballs or surrounds. You do need a DIN removal tool which is just two 4 inch long U-shapped pieces of wire - WalMart has them for $3.99 or you can bend a HEAVY gauge coat hanger into a U-shape with a 1 1/2 inch mouth. I used the wire part of a man's pants hanger because the wire is very stiff and just the right diameter. On the radio itself (as well as the AC control panel and optional tape player) there are two, 1/4 x 2 inch trim pieces on the left and right ends of each unit. They simply pop off, I used an exacto knife to fit between the radio and the trim piece. You have to look carefully because the trim pieces fit very close to the radio. With those off, you will see where the DIN removal tool goes. It slides into the two round holes on each side, to the depth of about an inch and a half. The removal tool can go in further, but you won't have any "handle" left. Actually you can feel when it's in far enough, by first a springy resistance and then a further movement in as the retension spring is compressed. Hold both of the DIN tools and apply outward pressure (away from the radio). This pressure will grab the radio in a pincher grip. Wiggle the radio left & right and pull straight out. There is enough free cable to allow the unit to come all the way out so you can unplug the cables.
Be carefull not to scratch the dash with the back of the radio. I removed by optional tape unit at the same time I was sliding the radio out. I found it was was easier with both loose and allowed me to clean up the cable routing and make it easier to run my new rear DIY speaker cable. The tape unit only has one cable plugged into it (the one from the radio), but there is a second connector on the back of the tape unit that appears to be the same as the one on the radio. I'd guess this would be to connect another unit in a daisy chain fashion, maybe a CD changer. I have not been able to find any pinouts of the tape cable.
I used slide connectors to connect my DIY cable to the back of the radio. I couldn't find connectors that were 1/8 wide, so I just cut regular 1/4 side connectors in half and after connecting the wire to them, used a piece of heat shrink tubing to insulate them (tape would do) because they are very close to each other. Remember the speaker's have polarity to keep them in phase etc., so label your wires L+ L- R+ R- at both ends before you put the radio back in. If your speakers aren't marked, a 1.5 volt battery will move the cone out in connected + to + etc. Currently I just have the speakers in the net behind the seats. This way I can move them around to find the best spot to permanently mount them. Mounting will be another adventure, but that's a different Mod.
Remove DIM hole covers with exacto knife
Locate the 2 round holes on each side
Homemade DIN tools
Insert DIN tools
Pull radio out
Back of radio
Back of tape unit