I looked at the backup lamp circuit diagram and it is a single wire going through either the reverse switch (manual) or the park/neutral switch (CVT).
It was not possible to tell from the schematics where exactly on the car it splits into two,but if I had to guess,it will be near one of the tail lamps. (However it could split before that! I'm not sure)
I printed the diagram and was going to post a pic of it here if you still need it but forgot to bring it home with me.
What is your plan with the circuit?
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View my fuel log 2014 Mirage DE 1.2 manual: 66.3 mpg (US) ... 28.2 km/L ... 3.5 L/100 km ... 79.7 mpg (Imp)