One question I'd have is whether or not your tail lights are working. I had the lights on my dash go out (the shifter lights still worked though) and my tail lights and parking lights were also out. After much investigation, it ended up being that the turn signal switch had gone bad. In order to replace it, you need to remove the cover around the steering column - we couldn't get the lower part of the cover off and subsequently also had to pull the steering wheel, then remove the turn signal switch (which also controls the headlights, parking lights, tail lights, etc), pop in a new one, and enjoy a life of dash lights and tail lights once again.
Do the interior lights work in the gear selector or the climate controls? If none of them work, suspect a fuse or something else. If it's just behind the gauges and all have gone out, then the board behind the gauges may be fried. But assuming none of those are the case, you'll need to remove the dash and the bulbs are located behind the gauges. Not a task for the timid.
Oh wow, there are big light bulbs for the headlights and medium size bulbs for interior lights and itty bitty lights for the gauges. If you need specific numbers for replacement bulbs check your owners manual. Cheers
make sure the selector switch for the lights in in the right position you may have put it to on accidentally
Check the bulbs, check the fuse then check the switch.
bad bulbs and or blown fuse
You need new bulbs
Probably the wrong bulbs or the brake lights are getting stuck "on". Or maybe a combination of the two. Check that you have the right bulbs and check to make sure something isn't keeping the brake lights on. FriPilot
the control panel on the rear lights goes bad. you can get a new panel on carstuff.com for cheap
Get bulb dye for the bulbs in the rear or use art supply colored plastic paper and slide a few sheets in between the gauges and the front panel
check for bad switch under dash above pedal arm, generally fail after 75,000 miles
Check the fuse, check the bulbs, check the flasher relay, in that order.
To replace the brake light on a 2000 Pontiac Montana open the trunk to reveal the housing units. Find the lights and pull the bulbs out. Replace the units.