This will NOT work if you have THIS:

This WILL work if you have THIS:

IF you already have this style stereo the process is relatively simple. You will have to: remove your stereo from the car, remove the factory amp from under the passenger seat, find a location for your new amp, mount it, and run power to it. This description assumes that you already know how to do all of those things. The process of creating the Din to RCA plug harness is very simple.

MATERIALS:

• Wire Cutters
• Wire Strippers
• Exacto Knife (best in delicate circumstances)
• 2 pairs of appropriate length RCA cable (cut off one end)
  • OR 1 pair extra long RCA cable (cut in half)
• Soldering Iron & Solder
• Heat Shrink & Heat Gun -or- Electrical Tape

THE PROCESS:

The first (and most scary) thing you will have to do is cut the din cable that connects the factory head unit to the factory amp. It's probably best to cut it more in the middle than close to one end. This way if you make any mistakes or if you are not happy with your end results, you can simply splice the cable back together and put everything back the way it was. Strip the shield and plastic covering back so that you end up with something that looks like this:

Note: The orange wire is a low voltage turn-on wire and may be used later - see note at bottom.

Each one of these pins connects to a specific wire. In turn each wire feeds something different on the factory amplifier. I determined this by disassembling the factory head unit and following traces on the circuit board, then using a voltmeter to check continuity to each of the pin-outs on the din cable.

Here's what I came up with:

Next strip the ends on the RCA cables (just one end) so that you have bare wire. Separate the two wires. The center pin on an RCA is ALWAYS the positive (+) lead. Outer collar is negative (-).

Note: I'm using a VERY short piece of very poor quality RCA cable. This is for example's sake only. Your cable should be long enough to reach the location of the aftermarket amp in your car. It should also be a fairly high quality cable to prevent any introduction of unnecessary noise into the sound system.

Now the tricky part:

You will SPLICE & SOLDER (DO NOT USE CRIMP OR TWIST ON CONNECTORS) each of the positive leads from your four RCA cables to the corresponding four wires on your din cable:

• Front Right: Yellow
• Front Left: Blue
• Rear Right: White
• Rear left: Green.
• ALL of your negative leads from your RCA cables will be soldered to the black wire on the din cable.

I've done ONE connection here for example's sake:

In this example, I have created the RCA output from the head unit to the Front Right input on the amplifier. After you have finished making your splices, insulate your connections with heat shrink tubing (electrical tape will do here, but is more sloppy). It's probably a good idea at this point to check the continuity of each of your connections to make sure you don't have any wires crossed or shorting on one another. For instance, the collars on ALL of your RCA plugs should ring the pin that corresponds to the black wire, but nothing else. If this is not the case, you should disassemble and find the problem. Before proceeding. Don't forget to label which RCA is for which input on your amp, or you'll be cussing yourself later.

IMPORTANT NOTE: You have one other hurdle to jump. MOST aftermarket head units have a wire (generally labeled REMOTE or AMP) that specifically turns on the amplifiers and other stereo accessories when the head unit itself is turned on. The stock unit's is the orange wire, but it doesn't carry enough voltage to work by itself. There are 2 options:

(IF you come up with a better solution to this problem, let me know.)

ONE OTHER IMPORTANT NOTE: If you plan on removing the factory amplifier as I did, you will lose power to the head unit. Seems someone decided that it was more efficient to loop the 12 (+) for the head unit through the amplifier and then to the head unit. SIMPLE FIX: Two blue wires on the factory harness go to the plastic plug on the factory amp. These wires are relatively larger than the other wires going into the amp. One comes from the fuse block (I'm assuming) the other goes to the head unit. Cut them off of the plug and splice them
together or just strip part of each of the wires and jumper them together. VOILA! Power now goes STRAIGHT to the head unit. You can now safely remove that crappy little black box amplifier under the passenger's seat.

These cables are also available commercially for $21 @ Autosoundgear - $25 @ Installer.com (MITAH) - $40 @ Logjam ; but it's much more rewarding to build it yourself !

-Jeff Crabtree
'91 R/T TT (3SI# 0499)

Questions / Comments ?

Special thanks to Paul Kempkes & Jeff Lucius of Team3S for their notes concerning the orange wire and relays.

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