This write-up will show how to very simply and cheaply install an aux input jack on the stock head unit, whether you have a tape or CD player. This will also work on many other GM radios because GM kept the wire locations the same. This worked on an Oldsmobile head unit.
The parts needed:
A 1/8" aux jack Part# 274-246 from Radioshack. (just go in and find what's left of what Radioshack used to be, a hobby style electronics store). This is a switching jack that will allow you to retain the functions of the tape or CD player too. It switches when unplugged. [2019 edit: Seems nearly every Radioshack is closed and their online store is not stocking these currently. An Ebay search comes up with a couple]
Other things you will need:
Wires, a soldering iron, and of course solder. I suggest a small soldering iron, and not a soldering gun as I've seen some people try to use. Mine was also bought at Radioshack, I have their 40 watt version and I'm very happy with it. For this project it's probably the biggest you would want. I was using .031" dia. solder that is great for small electronics.
A Philips screwdriver to remove the screws on the dash, pocket screwdriver, and if you're installing the jack inside the radio, a crazy small socket for the bolts on the faceplate(I don't have a socket small enough, so I simply used needle nose pliers) A "contraption" called helping hands is also extremely helpful for making small soldered connections. It can be bought at harbor freight. Part# 60501. A drill and drill bit just large enough for the jack to fit through, a 1/4 inch bit was my final size.(Although there seems to be 2 different versions with different outside diameters) Also I prefer a razor to strip the wires since they're way too small for wire strippers. Obviously be careful.
The other route you could go is mounting the jack in a place such as the center counsel or under a panel somewhere if you don't want to drill a hole in the the radio faceplate. (in case you think it looks tacky or something) It obviously doesn't look stock but it looks fine to me. In that case get some Ethernet cable and run it out the back of the head unit and to your preferred location (I have done it this way before) You will have to drill a hole in the metal case of the head unit to run the Ethernet cable out (still not hard to do) and another where you'd like to place it. You'd just be taking those 5 wires, and extending them. Ethernet is low resistance cable and will have no noticeable difference on sound.
Also remember if you have any burned out bulbs now is the time to replace them, you will be right there. My main display bulb was burned out so I bought a bulb from Radioshack and soldered it in the existing holder: http://www.backinblackgp.com/Radio_Lamp_repair.htm
This option was noticeably dimmer than stock, if that would bother you, get yourself a new replacement. Part# 16208443
I had one of the very tiny bulbs that are soldered to the circuit board go out. I had another faceplate from a JY so I just unsoldered one from it, and transferred it. I suppose you could just buy a micro bulb from Radioshack and solder it in place. Part # 272-1092. I've never tried this route, but I'm sure it would work.
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The first step is to get the radio out of the car. To do that, remove the lower kick panel with two bolts at the bottom, then pull the top and the clips should come out. They're metal clips. Remove the light socket and set it aside. The entire piece that goes from the headlamp switch to the radio is one piece, held on by metal clips. Just start firmly tugging all around until they're all removed. Then remove the wire harness from the back of the fog light switch. Move the steering wheel in the furthest downward position and remove the panel. You may start flashing your high beams and hazards like a crazy person, this is part of the job.
Once it's off, put it out of the way and remove the radio by removing the two screws that hold it in. Pull it out and remove the wire connector and antenna wire. Be careful with the connector, pull the block not the wires. Once it's out, take it somewhere you can take it apart and keep track of small parts.
Remove the radio faceplate with a pocket screwdriver on the plastic tabs all around. It will then slide off and you can remove the small ribbon cable connector CAREFULLY. There are two black tabs on both sides that hold it on. I was able to use four finger nails at a time to remove it. I will be explaining the method of mounting the jack inside the radio. I may touch on the other way at the end.
Remove the faceplate circuit board by removing the silver bolts. They were smaller than any socket I had, so I used needle nose pliers to remove them. Get a 1/4 in drill bit (or one size smaller to be on the safe side) and map out the correct area for the hole. Two locations are right under the time buttons, or just above the compact disk logo. Start drilling from the back side until you start to hit the plastic part on the front of the faceplate. Then cut a hole on the other side with a knife so that the drill bit doesn't tear it up.
This is literally the perfect spot for the hole when mounting it where I did. Not too high or low, you can see what I mean in the later pictures. It just clears the plastic panel that goes over the radio, and just fits under the buttons. I had to scrape the plastic a little because the threads didn't quite stick out enough. Make sure you can start the little nut that holds it in now, so when the wires are all connected you won't have to mess with it then, possibly breaking the thin wires.
Once the jack is able to be mounted, it's time to start with the wiring. There is a ribbon type of cable that goes from the amp to the CD/Tape deck. GM usually keeps the audio channel wire locations the same on most radios. Some are all white with one black wire, some are like mine and red with one blue wire. It's still the same no matter the color. First, remove this cable, making note of which end goes into the CD/Tape, and which goes into the amp. This is important for making the right wires go to the right spots on the jack. I put tape on the CD player side and wrote "C" on it. These are the channels you will need to wire up:
Cut those 3 right in the middle of the two connectors. You will need 6 wires total to solder to each one of those that will go to the jack. I keep old circuit boards and electronics around, so I was able to get the correctly colored wires. It's good so you don't mix anything up and also good for demonstration. The best method is to solder the wires. If you can solder well, that's a perfect and guaranteed connection. Keep in mind the furthest from the different colored wire is the left channel. Here is mine after all were soldered and taped:
Then take the two grounds and solder them together pretty closely so ground still goes to the CD player, and also run another one to the aux jack
Tape it up and re-connect the wire to the circuit boards. These are the wires you should have that will get connected to the jack, trim them if they're too long. You want at least 5 inches of wire to stick out so you can still work with it connected.
Now it's time to solder them to the jack. This will probably be the hardest part of the whole task for people who are new to using a soldering iron. You have to make the connections in under 3 seconds, or the jack will start melting. If you go to 3 seconds and it's not soldered yet, let it cool for a bit then try again. Here are the correct spots for the wires:
If you are installing it in the place that I am, you'll want to solder them so the wire is facing away from the threaded part. That way when you put the radio back together, the wires won't have to be bent much. This part is nearly impossible for one person if you're just using your hands. I used this little alligator clip contraption called helping hands from Harbor Freight. Part# 60501. I paid only $3 for it at the time. It helps incredibly. Here is the finished part:
Test your connections by gently tugging on each wire. Soldered connections are basically permanent without re-adding heat, so if they come off, they were going to anyways. Might as well fix it now while you've got easy access to it. You want it to look like this, very little wire exposed after the connection. After you've made sure they're not going anywhere, you can use hot glue to cover the whole area so the wires don't bend and break. Now secure it onto the faceplate, and bolt up the circuit board. It just barely fits:
Since it's in a spot where the mating circuit board goes, you will have to trim part of the main circuit board so that it will still go together. There is a tab that goes into the hole that the new jack is covering up. I just used some side cutters and cut a fairly small amount off. Don't worry, it doesn't have any electrical use. If you're mounting it above the compact disk area you won't have to modify any tabs. After it's all back together, push the wiring back into the radio and slide the faceplate back on. Make sure the wires go around the amp circuit board. Here is a picture of how the wires should be routed. I cut a part of the radio frame to make sure the wires would go in without binding, you probably won't have to do that but I did so I could be sure everything would work out.
In that picture you can see the tab that's cut, to the left of J9. (the j9 is in the background) When you push the faceplate on, make sure the wires go to the left and don't get crushed. Then push the faceplate on all the way, making sure all of the plastic clips seated. Reinstall the radio in the car and put the panels back on. Don't forget to reconnect the fog light connector.
At night. The jack lights up because the top of it is clear, letting in light from the rest of the radio.
How it looks with no cable.
With the cable
Enjoy having an aux jack that sounds great! You will need an audio cable to use it. Much better than how the tape adapters sound, it really sounds like a CD playing.
Remember that you need to actually have a CD in the radio, and hit CD/PLAY in order to use the mp3 input. This is because you're basically fooling the radio into thinking the aux input sound is what's coming from the CD. Once you unplug the aux cable, it goes right back to playing the CD.
Originally Posted by AmericanSoldier
