94 Z28 Click noise
 

If the radio Is on but at very low volume, then lowering the power window there is a click noise coming through the speakers. Sounds like an electrical click. When the radio is off no click. Radio has been rebuilt at local Delco store, speakers are new, power window motor is new. Can this be a electrical ground not being tight? Could it be loose on the radio or speaker or somewhere else? Also maybe the same problem or a different one but the speaker on the right side works for a while then stops working for a while. Thanks for any help.

check speakers and connections to speakers. might try something like this PAC CSS-100 (css100) Deluxe 10 Amp Noise Filter