Suddenly lost power to radio in my '94 Cherokee. Radio display does not come on when turning power **** on radio to ON position. Pulled radio and looks OK if I apply 12V to correct pin (#5) on back of radio. On harness connector, getting 12V at the (#4) BATT pin but nothing at the (#5) ACC/IGN pin with ignition switch in ON position. Thought I may have seen some low voltage (~4-5V) when I first checked it with DVM but it quickly went to 0 volts as if there was a charge on a capacitor but it bled off by my measuring it. The 15A fuse is OK in the fuse block as is the 7.5A fuse in the back of the radio. Any thoughts as to why no power at the radio harness?