No "secret button". Fuse #12 (15 Amps) in the engine compartment fuse box is an "always on" power source for the interior lighting and some other functions such as the clock and radio presets. (See page 12-10, 12-11 of the Owners Manual.) It can be pulled, but you will also lose the clock and radio settings, as well as the interior lights (e.g. ceiling light).