I did a swap a few weeks ago involving a swap from cassette without amp to cd with amp. The power connector should be 1 row with 8 wires. The amplifier patch cable (grey covering on it) should be 2 rows of wires and almost square in shape. I swapped the entire wiring harness to accomplish this task. However, I only recommend doing this if you seriously want a Ford head unit. Otherwise, go with an aftermarket unit. The cd player in the factory unit has the tendency to skip.
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'98.5 Mystique GS ATX
re-contented door lights
K@N Filter
Energy Suspension Sway Bar Bushings
Mintex Street Pads
Sidemarkers from CarBoutique
Pioneer TS-A6855's in all doors