Instrument panel brightness knob
 

Hi!

I recently bought a used (very) 2004 Isuzu Ascender (2wd, 4.2L L6 engine). To be brief, what the heck does the Instrument panel brightness knob push in and out for? I've clicked in in, so it stays in, then pushed it again and it stays out (extended)? Turning it changes the instrument brightness, but pushing the knob in, or out, seems to do nothing. Anyone know?

Does it activate a Nitrous Oxide injection device? Rotate the tires on the fly? Change the oil? Give me the winning Lottery numbers?

Not knowing is kinda driving me crazy. (even the "dealer" doesn't seem to know.)

Thanks!