Audio Systems: 1990 Ford Stereo with amp, ford mustang convertible, amp connectors

Question
I have 1990 Ford Mustang convertible.

It has a factory tape deck stereo with a factory amp.

I would like to install a Sony stereo with 4x52 watt built in amp.

I would like to use the factory connectors and by pass the factory amp using the factory speaker wiring.

The adapter plug I have found does not isolate the amp.  

Where can I find a harness which disconnects the amp.  

Also, is there any source of information for speaker wire color.  I'm not having much success determining which is + and which is - at the speaker.  Can this be checked with an OMH meter or other testing tool.

Thanks

Answer
Brian,
There are adapters to adapt an after market stereo to the existing factory amp, however I haven't found any adapters that will bypass the factory amp so that you can use the same wires to the speakers. If you would like to bypass the amp, simply unplug all the connectors on the amp and go to each speaker and write down the wire colors on them. The color of the wires on the speakers will be the same in the connectors that go to the amp and then on up to the connector for the factory stereo. You can order or stop by any good car stereo shop or even Circuit City, best Buy to pick up an adapter harness that you can connect to the connector that was plugged into the factory radio. At the amp connectors all you need to do is to connect the same colored speaker wires together. With the pig tail adapter connected to the connector in the dash, all you do here is to connect the wires to the new stereo. If you still aren't sure I can look at the wiring diagrams for your car when I return to my shop on Tuesday and get back to you with the correct wire colors for each speaker.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net