Aftermarket Stereo Amp Fuse Question

[slaughterrt]

I did a search but I couldn't find the right terms to search for to get a specific result. I did a search and found hundreds of results but none really helped me.
I have an aftermarket Sony head unit in my 99XLT and I am having trouble with one of the speakers. The back driver side speaker is not playing. The speaker itself is not the problem because I switched the speaker into a different slot and it plays fine. So it seems like the problem lies in the wiring. I have checked the solder joints and everything seems ok. I was curious if the amp in the Sony headunit has a fuse in it that maybe blew. I did not see any obvious fuses sticking out of the back of the headunit so I thought maybe internal fuses? I wanted to get some input before I start tinkering with the inside of the head unit.
All the speakers were working at one point, but I messed around with the wires while I was toying with the idea of putting in some tweeters. After I put everything back together (without the tweeters wired in), the back driver side speaker was not getting any sound. Any ideas would be greatly appreciated. Thanks guys.

Also, if it helps, the headunit says "Speaker Failure" sometimes.

 

[Dan Whitaker]

I'm willing to bet one of the wires to the speaker is pinched some where or the speaker wire is wire exposed some where and is toching metal.

 

[slaughterrt]

That is definitely a possibility that I didn't think about. It is grounding out somewhere. I will have to check into that. I'm still curious about the internal fuses inside the headunit (if there are any).

 

[scucci]

If you have rear aux controls and you are going through the stock wiring using an adapter harness you might have a problem in the aux control circuit. Cure is to remove the rear speakers wires from the aux control unit and splice them directly to the speakers.

 

[PandorasCustoms]

Most aftermarket head units have a fuse tied in directly on the back of the unit.

You will see in the below image that there is a small 10amp fuse that is right below the wire harness connector (I took this from a Sony CDX-GT700HD). You usually can not get access to the fuse while the harness is connected.
The fuses on the head units generally (Everyone I have ever installed) affect all controls of the unit. If the fuse blows, the unit will not power on at all.

Also, I know of several units that have a grounding protection to keep from blowing the fuses. It will stop playing if it senses a short in the speaker connection.