Ford part number C9WY-10K843-C Whereas the engineering number printed on the backside of this PCB is the same red vs blue there is a distinct difference. Many people get confused with the numbers printed or cast into parts thinking that that is a part number when really it is a casting number or engineering number and may or may not resemble the actual part number listed in the MPC (Master Parts Catalog). 1969 Standard Cougars used the blue PCB (printed circuit board) up until 2/17/69 and after 2/17/69 and all of the 1970 Standard Cougars used the red PCB.
Below is an example of the 1970 Cougar standard underdash harness plug. The late 1969 harness would be different.
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