Great.

Now, what kind of improper wiring could cause it? What would be wired incorrectly to make it power on, yet produce no sound? Otherwise, how am I to know where to start looking?

 

Find a wiring diagram, as previously suggested, and make extra sure that all the new headunit wires match the factory wires. Speaker Left+ and Speaker left + and the like.

If you have the front right speaker + hooked up with the back left speaker - it will never play anything

 

There was sound, at one point. I know the speaker wires are correct. It DID play sound. It just doesn't do it all the time, and it will randomly stop playing sound. Thus, the speaker wires are correct. I have them correct.

What else could cause the problem?

 

If speakers are good, and hed unit is good, and wiring is correct, then it is working. If not, one or more of these is not true.

Check HERE for wiring diagrams. Click the link for the year closedt to yours.

 

check your head unit ground wire.
make sure its secure to a screw in the dash.

what is intermittent? power to the head, or sound from the speakers?
i would temporarily remove the speakers from the door and set them on top of the dash for debugging. run a new, short piece or wire to them.

 

I never lose power to the head unit, but the sound from the speakers is. Also, it is not individual speakers not playing, but all of them. Thus, I assume it is not the speakers, but the head unit.

 

Two of them exhibiting the same behavior though? That seems rather strange.....

 

EvilBigHead is not crazy. I am dealing with the same problem with my 1999 Ram 1500. It is the factory radio with the power button, cd player and cassette player. The truck has been sitting for a couple months and I just replaced some brake lines. I went out to check the problems and had a hard time keeping it running. Hopefully it's just some bad gas.

Anyway, I figured I'd listen to the radio while I sat there. Turned on the radio, no sound. change stations, adjust volume, play with equalizer, on/off, insert cd, no sound. Everything "looks" like there should be sound but no sound. Then suddenly I started getting sound from the rear speakers only. A minute or two later the sound went out.

 

I assume you are Using an aftermarket stereo? if so and you have run new wires to each speaker, unhook all speakers, verify there impedance, Should be 4 ohms, then reconnect them one at a time testing each one as you go Hope this may help

 

Just went out and pulled the bezel and slid the radio out. Radio came on, just back speakers. Lots of bass. Then it the sound cut out. Tried playing with the wires and plugs, nothing. sat back, looked at the radio, and the sound came back on. After a while it would die again. One time I let it play for a while without touching anything and the volume dropped a little before losing sound. After a while it came back. I did notice that the left side of the radio, where the volume control is, was getting warm.