Car Stereos: Amplifier issues, ac volts, annoying habit

Question
I have a 04 Suburban.  About 1 month ago, the front speakers started cutting out occasionally so that they were  barely working, then it got to be more and more.  I replaced the OEM radio with a new radio with the proper harness and it seamed to work fine for a couple of days then it started to do it again. Sometimes it will be one front speaker that does not work, sometimes it will be both.  Sometimes both fronts will be out and only one rear will work.  I do not have a Bose system.  From what I have read, there is an amp somewhere, but I can't find it. Any ideas?

Answer
Hi Steve,

Most Suburbans do have a factory amplifier, although they don't always run all the speakers.  In some cases, the stock amp just runs the rear door speakers, and the front door and rear roof speakers are driven directly from the head unit.  It's possible, though, that your amplifier is connected to all six speakers.  The stock amp in your truck should be located behind the glove box.

I haven't heard of an issue like yours, so I'm not sure what's going on there.  If I were troubleshooting this issue, I'd use a multimeter set for AC volts, and test the speaker wire at various points along the line: behind the head unit, at the factory amp's output plug, and at the speaker itself.  If you find AC voltage on the source wire going into the amp, but not the speaker wire coming out (for example) then that's a pretty clear indicator that the factory amp is the problem.  It might be a pretty time-consuming process, though; and intermittent problems like this have an annoying habit of fixing themselves temporarily when it's time to do the troubleshooting.

Good luck!

Brian