A 1991 mitsubishi montero , recent dead battey and no park lights

The rheostat is the little dial on the dashboard that alters the brightness of the dash lights. It isn't under the hood. If your turn it all the way down until it clicks, it will turn off the lights. It will be in your manual.

https://www.google.com/search?q=2000+mitsubishi+montero+sport+manual
https://mitsubishiforum.com/forum/mitsubishi-montero-montero-sport-14/no-lights-dashboard-34680/
https://www.google.com/search?q=2000+mitsubishi+montero+sport+dashboard+lights+not+working

..

Your battery could be dead
Try to charge or jump the battery

probly bent bracket for sensor on one of the backing plates

the battery might be dead if u charge the battery and it does not crank over or make a clicking sound after the battey is charged then u need a new starter

My suspicion is brake light switch has gone bad. It's located just above brake pedal below dash. (small plastic switch with a couple of wires - pretty simple fix)

Sounds like you need to replace the switch that goes to the parking brake. This switch is located close to the parking break and it's only function is to remind you that the parking brake is on. You can get this part from any major part store.

Check the ground to the back tail lights, the ground may be poor and when the lights are on and may draw through the running lamps or vise-versa. Inspect the bulb connections and using a multi-meter or inspection light check for 12V DC at the terminals. Have a friend pump the brake pedal to check the brake lights to be certain the switch is ok (the switch is actuated by the brake pedal just under the dash)

I hope this may have assited you,
Tom

check the fuse box on the driver side of the car underneath the dash near the door the fuse is probably blown

if its the water temp light id say it needs water , level low. hope this helps?

Often stereos have a dash light feed to dim the display when the park/head lights are switched on. I suspect this wire may have been shorted during installation, causing a fuse to blow. Are you certain that the fuse for the park light circuit is intact? I know you have checked them all, but I have overlooked blown fuses in the past, easy enough to do. The best way is to use a test light with the ground clip to a good earth point, and probe both sides of the fuses (ignition key on, park lights on) to see if the test light lights up. If it only light up on one side of the fuse, it's blown.

Hope this helps.