i have this weird electrical problem which suddenly appeared after (1) my alternator belt was replaced; (2) i moved the CD changer cable around while putting some foam under the back seat.

basically, the HU dies under heavy electrical load. for example, high beam and A/C is on. if the RPM gets really low, or a signal light is engaged, or i roll down the window, the HU will *sometimes* turn off spontaneously. am not sure if the entire electrical system is affected, or just the HU.. but so far no other electrical parts are misbehaving.

i have already replaced my alternator with a 90A unit, and this problem didn't exist until the two events i've listed above. any ideas?