Lately iv noticed that my driver side speaker would some times work on and off. Then I noticed that the passenger window didn't want to roll up and down. I have tried looking at the connections to the speaker and at the back of the radio.
If we are to assume these two things are related, check for broken or frayed wires between the driver's door hinges. For just a speaker problem, switch the left and right speakers side-to-side. If the left side still acts up, suspect the radio or the wires between the door hinges, (for a door speaker, not a dash speaker). If the right side acts up now, it's the speaker.