Intermittent Speakers

[EndGame410]

Hey, guys, been a while since I've been on here, but in the past month or so, my 1996 Explorer Sport has developed some odd issues with the speakers.
While going on rough roads/terrain, I've noticed that the front driver's side and rear passenger side speaker have intermittently become softer. Not completely cut out, just softer. I have an aftermarket head unit (It's a sony, but I don't know all its details; it was installed when I got the car a year ago) installed, and I just took that out today looking for poor connections.
My search yielded nothing. All connectors appear to be put on correctly, and everything *looks* in order. However, after reconnecting everything, the problem persists. I have had the door panels off for a couple days, fixing the window motors, and I checked the connections to the speakers as well. Still nothing.
My fear is that, since it appears as though the installer did not really know what he was doing (several obvious missed steps in installing the DIN adapter), he messed something up with the harness.
So, my fellow explorer owners, where can I go from here? I've done a lot of troubleshooting and searching on here, but I am really at a loss now that I've eliminated a poor connection to the HU itself.

 

[drdoom]

Possibly a wire broken near the door jamb?

 

[EndGame410]

Okay, I took the speaker out of the door and tested it. 6 ohm impedance. So the speaker is still good, so it seems. I'm fairly certain it's a wiring issue, but I'm not sure how to troubleshoot that without cutting wires. I guess I'll take the head unit out again and test the resistance of each wire, see if one is split somewhere.

 

[J_C]

If it's the speaker in the door I would suspect the wire broke in the door boot, hinge area, same as the other wires going through that area are subject to breakage from flexing when the door opens and shuts.

 

[EndGame410]

Okay, I think I've found my problem. I took the head unit out and messed around with the wiring behind there. Turns out, if I move the main bundle of wires, the speaker stops working. So there's the issue. Now, how can I go about fixing this now that I've found it? Should I hunt down the exact problem wire and cut around it, splicing in a new section? Or is there a better way?

Here's a few pictures I took behind the console: http://imgur.com/a/4c2ec

 

[J_C]

EEK! Peek behind some of that electrical tape to see if they soldered it or just twisted it together. It should be soldered and ideally, shrink wrap tubing over that, or purists would prefer you soldered connectors on.

Beyond that I can't make heads or tails of it besides suggesting you wiggle individual wires trying to keep the rest stationary, focusing on the colors for the specific speakers cutting out.

If the main power leads are just twisted, definitely solder those and they may even need oxidized strands cut off to expose cleaner copper to get a good connection. If the unterminated wires have any chance of shorting against anything they should have a wire nut (or cheaper and smaller) heatshink tubing pulled halfway onto them to insulate them better.

Heatshink tubing with a glue liner works better for that. You can leave a tail on the heatshrink sticking out past the end of the unterminated wires and cinch the tail together with pliers while hot.

 

[EndGame410]

EEK is right. I don't actually think the short is where they spliced the wires. Wiggling the wires around has made me think it's farther back in the electrical tape. Possibly where they join the larger bundle and turn sharply. Either way, I need to remove all the electrical tape, a sticky job to say the least, and start testing individual wires.

I haven't been paying much attention to color because I'm colorblind, so I'll make sure to get someone out there who can actually see to tell me which wires are which. I believe the two wires coming from the speaker are a slate wire with a black stripe and an orange wire. I could easily be wrong, though.

I guess it'll just be a matter of time and hard work to get this fixed.

 

[EndGame410]

Okay, I think I fixed it. I soldered all the connections, put heat shrink tubing on them, and tested it sitting in the driveway. So far, all the speakers work equally well.

I'll take it for a test drive tonight and update. I also made a video of the process (head unit removal, wiring diagram, soldering connections, and putting on tubing) as I did it, so if there's any interest, I'll upload it.

 

[J_C]

Good to hear... Might as well upload it. The older these get the more people will need to be tearing into them.

 

[EndGame410]

Okay, didn't fix it. I drove on the bumpiest road in the world (I have to drive on it every day) and it cut in and out. The behavior was different, though, so obviously I did something to it. I guess I'll hunt down a broken wire. *sigh*

 

[J_C]

^ Well at least you got that out of the way and it has eliminated both a possibility and a later problem from happening.

 

[EndGame410]

Plus it's a whole lot neater without all that electrical tape :3