I have a DVD player, an XM radio and an MP3 player that I'd like to wire into the stock head unit of my '03 EX.

Before anyone responds with the "use a y-adaptor and plug them all in at the same time" - I can't. I've read on another forum, and been told by a Radio Shack employee, that that's a bad idea as you can harm your electronics that way. (Basically because you have input going into something that was meant for output only.)

That being the case, I purchased a 4-way stereo selector from Radio Shack for 20 bucks. (Attaching the pdf link to the manual so you can see the connections on the back.) The one I bought actually looks a little different - it's smaller and is black - because it's the model that's being discontinued for this one:

http://www.radioshack.com/images/ProductCatalog/Manuals/OME15-1983.pdf

It's intended for home stereo use, but the only difference between home and car in this application is the size of the plugs. If placed in the glovebox, I can run the "output" RCA jacks from the selector control to the Aux input of the radio. Then, run the wires for my 4 inputs. (4 including the Aux connection on the dash). Of course, I'll need a few plugs/adaptors to make the transitions from the 1/8" plugs to the RCA plugs.

In theory, this should work, and all wiring will be hidden. Plus, I'll still have the original Aux plug. The only thing I'm losing is the small amount of space in the glovebox.

So, what does everyone think? Comments? Questions? Concerns? I have no experience with audio wiring, so this should make for an interesting weekend project......

first a Y splitter will not be an input into an output jack. I use a Y splitter for my XM and mp3 player and have no problems. I do shut off the one im not listening to though I suppose i could just turn the volume all the way down. but a splitter takes 2 outputs and puts then into one input instead of vice versa.

My main concern with your setup is all those connections will be a playground for interference. You will have to convert the 1/8 plug into RCAs and then plug those into the switcher. I dont recall ever seeing a 1/8 to RCA converter. My guess is you will go from 1/8 to 1/4 to RCA and that will be even more likely to cause interference. Good luck tho.

Here's a 1/8"/RCA cable: http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=42-2483. This particular one is 6feet long, which should do the trick for all of my installs. I'd like to find a shorter one for the dashboard Aux, so I'll have to keep looking around.

Hopefully, I'll get some work done on it this weekend and be able to post some pics next week!