something like this perhaps.....
http://www.jameco.com/Jameco/Product...ns.pdf?CID=CLB



In this example he used 3.5mm jacks. You could use RCA or even USB I suppose. Or a combination of all. Also, they tie the negatives of each input and output together so rather than four wires... R-/R+/L-/L+ you only have three R+ / R-&L- / L+. Thus the "three pole" switch at the heart of it all....

http://www.jameco.com/webapp/wcs/sto...0001_101566_-1

For a 4 pole 5 position switch you can go with this I believe...
http://www.ebay.com/itm/like/2806052...lpid=82&chn=ps

 

My 98's CD sounds like it is trying to load a CD 2 or 3 times and then I get the ERR on the head unit. Any suggestions for a CD unit with these symptoms?

There were several home burned CDs left in it from the PO and I've tried some commercial ones with the same ERR result.

 

Philwarner: Before you throw out your CD changer, you might try taking it out of the vehicle, removing the cover and cleaning both the lens AND the spinner (where the CD sits). Often the spinners get coated with dust to the point where it loses traction and the CD doesn't reach speed, or spins erratically and the unit doesn't know what to do. That's a common issue with CD players, especially ones in cars. Clean the spinner with alcohol. If its rubber, there is such a thing as Rubber Revitalizer (a miracle product for like VCRs, tape deck pinch rollers) that is a couple bucks a bottle and good to have around. While you have your CD changer apart, check for any leaking or burst capacitors too. Capacitors and bad solder joints are the top fail items. Unlike resistors, chips and other solid state components, Electrolytic capacitors WILL eventually dry up, leak or burst. That's just what happens as they age. They say, the majority of failed electronics can be traced back to this. It's worse in cars that get very hot inside because heat is the enemy of electrolytic capacitors. When they age or go weak, they don't modify the electrical signal as well as when new. Eventually when enough capacitors in a circuit get far enough out of spec, the electrical signal downstream gets so out of whack that the chips receiving this signal start doing goofy things. Bad capacitors usually have a domed top, brown goo, or dried up stuff at its base. Capacitors can be tested with something like an ESR Meter, which is outside most mechanic's took kit (but definitely worth buying if you're interested in doing electronic repair -- see Ebay), but for now, I would just do a visual check. Capacitors will work in a wide range. Generally, I've found that you can usually spot problems visually (or by smell too). Rarely are they bad and don't leave a visual clue. Fortunately they're super cheap (Amazon sells them) and easy to replace. So, I would definitely check them. There are youtube videos on how to do it. And the benefit is, other parts of your vehicle that use things like Capacitors and other electronics are easy to ID and repair for literally a couple bucks once you learn a few electronic basics.

And while on the topic, the same thing is probably true of the failing head unit described in the O/P. Head units are subjected to 150 degree heat for who knows how many hours and days. Heat is the killer of electronics. That's why companies spend small fortunes to keep server rooms as cool as possible. I've repaired a number of car stereos that had failed capacitors, and a few that had bad solder joints. The first thing I look for in a failed electronic device are the capacitors and a lot of time you'll see one or two right off the bat that have crapped out and there's your problem. I'm going to give you 3 million dollar tricks that will aid in helping ID many electronic failed components. While it's good to have scopes and fancy gear, the fact is, the vast majority of electronic problems come down to: Cold solder joints, bad connections (like ribbon cables) and failed electrolytic capacitors. Resistors, chips and transistors rarely fail on their own. Many problems can be ID'd and resolved by using the following:

1) Visual Inspection - Visually inspect the board for bad solder joints (grayish or lighter color than normal joints) and leaking, failed components ...anything loose, burned areas on the board or discoloration. A lot of problems can be spotted visually. Use your nose too because anything that smells burnt is worth looking into. If you're looking at power supplies and larger capacitors, make sure you discharge them. Worse shock I ever got was from a large capacitor. They can kill too if big enough. Look on Youtube how to make a discharge device, or just short with a screwdriver. A lot of problems show up visually. As you become more experienced, you will get a better sense of visual clues to look for.

2) Wooden stick trick - While the electronic item is opened up, and turned on (observe safety techniques and use a wrist strap), tap around on the board and components with a sharpened wooden dowel (like pencil sized, but don't use a pencil). Often tapping on a bad item may make your device work, crackle or show an area to be investigated further. This is an old-timer's trick and you can ID a lot of failed solder joints, and circuit board problems this way. My wife's Jeep car stereo was crapping out and there were several bad solder joints at the main power transistors. All it took was a touch from the soldering iron to fix.

3) Freeze spray - By going around the board and spraying certain components with freeze spray, you can zero in on problems and usually even down to the exact failed component. Get a can of freeze spray (Amazon or Ebay), and spot spray. Bad solder joints will tighten up, and weak capacitors will suddenly work better. Of course, failed capacitors won't work, but they leave a visual trail. Freeze spray is an invaluable tool. Any good mechanic that works with electronics should keep a can around. Beyond that, resistors and transistors can be check with a multimeter, but these are in the minority of problems.

Speakers - I had to re-foam the subwoofers on my 98. It only cost about $10 and didn't take very long. Sound great. I've refoamed a lot of speakers. The best thing is to buy foam for a lot of speakers at once if you have others to redo because the shipping will cost more than the foam. Speakers contain about 4 or 5 different components and of those, about 2 can actually fail (the cone, foam or coil). Car's are a tough environment for speakers. Cones become brittle (but generally don't tear unless abused), foam rots (inevitable), and connections to the voice coil can corrode somewhere along the way. All are pretty easy to track down and fix.

 

In my truck, I don't even need to have the 6 cd holder in the unit. I get the message "ND" for "no disc" on the head unit. The audio still comes from the CD line (which I have spliced into). I figure this saves wear and tear on the CD changer.

 

Thanks, Mark G, for all the info which I will copy and save for the future reference. It turned out my CD problem was my own stupidity; I'd never noticed the instructions on the clear plastic CD trays that tell you to put the CDs in label down and I was loading them label up as you do in most other devices. Turning them over and then remembering to close the sliding door had my CD changer playing as it should, especially after I figured out that the station memory buttons also choose which CD plays. Now Jimmy, James, Randy, and Willie can ride along with me for an enhanced Disco experience.

 

Hey, I've done that before too! (laugh)

 

Cleaned it all up and now it works! Even driver side front speakers kicked on! Lol. Replaced rear hatch speakers.

 

Installed a Pioneer AppRadio the other day and am very pleased with the results. The systemis pretty effin loud. Even impressed my 14 yr old son. lol. Tied it into the stock amp. No aftermarket harness. Just followed the posted wiring diagrams from here and crutchfield to see what was what. Pain in the *** but was cheaper and didn't have to wait for shipping... I was gonna stick with stock head unit but it was not practical for what I need. Now I have full smart phone adaptability via my touch screen head unit. I do have a tiny annoying buzz with the truck on but I bought a in-line filter for the power lead that I'm gonna install at my earliest convenience. All the stock grounds are soldered then shielded into a ground I made and double checked them too. Buzz changes slightly with lights on or acceleration so I'm pretty sure its the power lead.

 

Which unit did you get?

 

AppRadio 3 by pioneer. Bad *** unit. Does everything I need : Bluetooth, iPod, Aux, GPS via wake app, downloadable apps, great sound and easy to use.