Ford's factory radios and wire harnesses contain green wires with orange stripes and light tan wires with green stripes for the right front speaker. The right rear speaker has an orange and maroon wire and a black and purple wire. The left front speaker has a blue and white wire and an orange and green wire. The left rear speaker has a brown and yellow wire and a gray and blue wire.
An alternate color scheme for the wires is to have a white and green wire and a black and white wire going to the right front speaker. The left front speaker is connected with an orange and green wire and a black and white wire. The right rear speaker is connected with a pink and blue wire and a green and orange wire. The left rear speaker is connected with a pink and green wire and a pink and blue wire.
Ford does not use wire colors consistently, so two vehicles that are the same model may have different colored wires if they were built in different years. Ford uses three different wiring configurations in its cars. It is not uncommon for car manufacturers to use up to 30 different wire harness styles and color codes for the wires in their cars. When installing a new stereo, it is good to keep the original wire harness intact so that the factory stereo can be reinstalled easily.
Use a test radio to test car speaker wires when working on a car stereo, and use a 1.5-volt battery to test speaker polarity.