Car Stereos: speaker problems, loose wire, new radio

Question
i have a 99 tahoe and i installed a new radio and about two weeks later my rear door speakers stoped working the front door and rear headliner speakers are still working %26 my subs still work so how would i go about fixing

Answer
First, I would pull the rear door speakers and see if there is a signal getting there.  If not, you know there must be a problem with the power supply.  If the speakers are powered directly from the new radio, there may just be a loose wire behind the radio.  If the speakers are powered from another source (amplifier), the amp may have some connection issues.  After finding no signal to the speakers, I would pull the radio and double check all of the connections and hopefully a loose wire will be discovered and solve your problem.  Hope this helps, Scott