It appears there is a problem with the power feeding the switch on the Pink/Red wire in pin 2.
With C1 disconnected (14 pin connector), and looking into the pin side of the connector with the locking tab on top the pins are numbered as
-7 -- 6 -- 5 -- 4 -- 3 - - 2 -- 1
14 - 13 - 12 - 11 - 10 -- 9 -- 8
Wires Colors -
Pin1 - Black/Yellow
Pin2 - Pink/Red
Pin3 - Light Blue
Pin4 - Black/Orange
Pin5 - Black/Orange
Pin6 - Light Green
Pin7 - Light Blue
Pin8 - Yellow/Black
Pin9 - Black/Orange
Pin10 - White
Pin11 - Pink/Dark Blue
Pin12 - Yellow
Pin13 - Pink/Light Blue
Pin14 - Tan
Power for the tails/markers is supplied on pin2 (Pink/Red)
When the lights are turned on it is switch to pin1 (Black/Yellow)
The Yellow wire in pin 12 has nothing to do with this.
With this connector disconnected, verify that there is constant power at pin 2 (Pink/Red). If it's NOT there -
1) Check Fuse 'F' (20A). There should be power on both sides of this fuse. If there is power at the fuse, follow the Pink/Red wire from the fuse to the switch and repair as necessary. Be careful here, as this wire is live all the time.