I'm saying the battery cables being loose or corroded can cause the dash light problem. That's one of the first things that needs to be checked any time there's an electrical concern. When you say "test the battery", you mean check the static voltage. To actually test the battery, you would apply a load and measure the volts @amperage (example 10.1V@350A). You should have the same voltage at the radio harness as at the battery. Now please answer, did you solder the wires in the radio harness? Read this
http://www.automotiveforums.com/vbul...d.php?t=950229