As I mentioned, light sensor (located on passenger side of dashboard, near the defroster) is a simple photodetector. Depending on amount of lux (light) delivered on it, given it is placed on auto position, light switch closes or opens taillight circuit (whole logic is done by light switch). In late evening/night, dark environment it should put tail lights on just as you turn key into on position. Then, driving during daylight with low velocity, as you drive into the tunnel it should turn on tail lights, but also it will turn it when you drive slowly under large bridges etc. It is unlikely to reprogram switch behavior because of light force recognition (materials and technique used in its production).
Further details are mentioned in shop manual.
Utilizing aftermarket DRLs and auto light switch made me forgot about light switch on daily basis