Check Back-Up Light Switch (Mt Model)
WARNING: This page is about a different car, the 2015 Subaru XV Crosstrek and 2015 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.
Refer to "INSPECTION" of the "Switches and Harness" in "MANUAL TRANSMISSION AND DIFFERENTIAL" section. < Ref. to BACK-UP LIGHT SWITCH , INSPECTION, Switches and Harness.>