99 Cherokee Front speaker help

In my 99 Cherokee Sport I have the Factory Cd w/ cassette and their are times when the left front speker dosen't play (usually the first time I turn the radio on for the day and eventimes after that). If I turn the volume up some then lower the volume, the speaker will play.

Another thing I noticed was that if I use the balance/fade control and set it so only the left front speaker will play, it sounds almost muffled compared to just the right front speaker.

Could this be a problem with the speaker itself or in the headunit? I was told that their may be a cold solder join in the headunit causing this, OR that the speaker may be getting wet or some other problem with just the speaker.

Any ideas?

I finally got around to removing the door pannel and took a look at  the speaker. everything inside was dry (and it's been snowy and rainy here) so that emiminates the wetness.

Next, I went to unplug the speaker and this is when it cut in and out. the Speaker metered at 8 ohms, so I guess it's alright, but it still dosen't seem to be playing at it's full potential, like the right speaker.  I reconnected the speaker again and played with the connection and this seems to be the reason why it plays sometimes and dosen't play others.

Would this also have to do with why it dosen't sound as good as the right speaker ?

I've seen the left-front speaker wiring go bad on two late-model Cherokees so far; I'm not sure if this is just a coincidence.  Of course, though, that's the door that gets used most often....so if there's a flaw in the car's design, that's the door that would give you trouble.

There's plenty of room in the rubber boot going into the door.  Instead of spending a lot of time to find the exact place where the wire had trouble, I just ran a length of new wire from the speaker into the driver's kick panel, and tied into the factory speaker wires there.