Learned valuable lessons today!

[slowcpe]

That stinks but I think with following bustamante's advice and posting your results, you've got a wealth of knowledge on this board to get this ironed out on your own. I know that's not what you originally paid for, but sounds like the install may need to be chalked up as another lesson learned. Especially on buying used car audio gear.

Car stereos are actually pretty simple setups so tracking down the culprit in a truck shouldn't be bad. Making sure you have power to the amp is the big ticket and check fuses/grounds first.