Audio Systems: Ford Premium sound system, premium sound system, rectangle shape

Question
I have a 1994 ford E150 with a premium sound system.  The is no sound from the speakers. The radio tunes and the clock in the radio works. The head checks out Ok and the amplifier physically looks good - no burnt components. I'm assuming I have a wiring problem ie no 12Volts going to the amp. There are two plugs going into the amplifier.  The small square one has about 4.75 volts on each pin which the radio shop said is OK. Its connected to a cable going to the head. The other plug is rectangle shape and has two rows of pins. One row has three pins with no wires connected separated by a space and then three more pins.  These pins have a dark blue wire, a back  wire with a green stripe and a light blue wire with a white stripe. Are these the power and ground wires?  The other row has around 8 pins - I'm assuming are speaker wires.

My question is -Am I'm on the right track expecting that there should be 12 Volts coming to the amp and are my assumptions reasonable?  

Answer
Ray,
Most premium amps will have two 12 sources to them. 1, 12 volt hot at all times and 1, 12 volt switched with the stereo turned on. Please give me the complete model number of the stereo and of the amp and I will look over the service manual and tell you what wires are used for what signals and power.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net