No sound out of speakers

[Plum Ranger XLT]

About a year ago, I installed a aftermarket radio in my 1995 Ranger using a setup that connected the radio to the factory wiring with no splicing. Recently, I was getting no sound out of the speakers and I had to put the factory radio back in. Any ideas?

[Ranger SVO]

Well if the factory radio works, I would assume that the aftermarket radio died. If you have a volt meter it would be easy to check. Plug the radio in and turn it on. measure the voltage on each speaker wire. It should read 1/2 of battery voltage and all voltages MUST be the same within a 1/10th of a volt.

Now if all the voltages are the same except for one and its reading is 0, then disconnect that speaker and see if audio returns.

If the voltages vary greatly the outputs in the radio are dead.