Trouble-shoot SAS TA850C in 07 Escape

Sorry, here's the post without formatting:

Hi, we just purchased a SAS TA850C (8” amplified sub) for installation into a 2007 Ford Escape with the standard 4 speaker 6 disc stock CD/MP3 player.  Installation was completed using a Stinger amp kit.  The power lead is fused and runs directly from the battery and reads 12v at the sub’s wiring harness.  Ground is solid and runs directly into an unpainted chassis bolt.  The remote power wire is patched into the switched accessory wire on the head unit and reads 12v at the sub wiring harness when the head unit is turned on, 0v when the head unit is off. The high level inputs are connected to the head units stock wiring harness as follows

Right Rear Spkr (-) Orange w/ Maroon Stripe

Small voltage readings are obtained from both pairs of high input wires when the stereo is in operation and the high level input wires are clearly carrying a signal as they run an old 6x9 that I had laying about.

Thank-you very much for the help.

The power light was coming on.  However, I moved the ground and managed to get the amp to work, sort of.  It would seem that there is maybe some kind of feedback occurring through the speaker level inputs as I blew the fuse for the head unit. After replacing the fuse, if I leave only one side of the speaker level input wires hooked up the system functions (although with a fair amount of noise and reduced output), however as soon as I put the other side into the amp it sounds much better, but when I shut off the car and restart it I cannot get sound from any speakers at all (zero sound from the entire system) until I unhook the speaker level inputs from the amp.

I also tried a line output converter to avoid the high level inputs and I got an oscillating "thud-thud-thud" from the system.  I swapped the left and right wires and then the polarity and still got the oscillating noise.  I’ve checked to ensure I have the correct output wires tapped but I understand that Ford is notorious for changing wire colors (However, I also checked the PIN placement at the rear of the head unit from a Scosche wiring kit so I’m pretty sure I’m on the correct rear speaker wires).

I also tried disconnecting the remote power lead and jumped the amp from the main power lead and it didn’t solve the problem. It's amazing that such a simple instal could be so frustrating! Any further advice you may have would be greatly appreciated. BTW Happy New Year.