Car parked car ventilation retrofit

[eL_cHe]

Hi ppl, i have upgraded my 325is with many things, such as 3rd brake light, parking sensors, remote locking, autodipping rearview mirror, etc. The thing is that I would like to have fully features of the 18 button OBC working and am looking for some info on how to get the TIMER function properly working, i mean, i find the stopwatch function useless and would like to wire it to have the parked car ventilation instead.

Any issues out there?