'00 TJ brake and 4way lights not working

Replace the hazard flasher and brake switch. No year make or model.

i think you ment IP cluster backlights dead not warning ligts
that is real the huge parking light structures.
a blown fuse. it is, why not test them ? first.

either cab fuse or the engine bay fuse box.
12vdc on both sides of fuse, is a good fuse, key on.
100% accurate test. no guessing. ever with voltmeter.
(rare exceptions a car with a ground fuse, very rare)
so lets do this the hard way, no fuse tests......

but hark the fsm is free. why not just look at the road map er, schematic, (wiring diagrams)
lets do HL , they are hot all the time, keys lost .

your car is a TJ so having a TJ book is spiffy , no? KEEN?
lets do that. TJ wiring
click TJ
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

now click wiring, following me?
posted this 100 times,., here.

my guess is parks are dead High beams good, right, ?????
yes then go to JUMP 1.
HL dead highs and low beam? parks out.(aka TAIL)
PDF page # 92
fuse PDC #17 blown? kills cluster dead too
JUMP1: parks dead.
had lamps is fuse #1, jb (page 134 pdf)
then PDC fuse 4 and 10 (lows and highs)

PDC is engine bay box.
JB is cab box.

so my guess (hard way)
fuse 10 and CB 24 was blown. kills high/low beams
Fues1 and 4 only parks. and cluster dimmer feed.

page 134 makes all this childs play with a meter.
volt meter.

That is a sign of a bad bulb, flashing fast. Check that rear bulb.

The turn signals and the brake lights go through the hazard switch. Try cycling it a few times and see if that solves the problem. If the fuses are good and the 4way's don't work, I would suspect that switch.

there are 2 flashers for that system, one works the turn signals, the other work s the 4 ways.

The first thing to do is check the fuses, the fuse may have blown, maybe to a short or bad bulb, start with the fuses and also make sure the 4way hazard lights switch is off.

Try having someone push on brake pedal at the same time thay move the turn signal lever up and down slightly to see if your brake lights work this would tell me that you have a faulty turn signal switch because GM runs the brake lights thru the turn signal switch so they work if you are driving with your 4way flashers on.

check for a crossed filament in the brake lamp bulbs on the right side. have seen this many times before- usually at 5:00 on fridasy when i was on the way out the door
good luck

Make sure you have the right bulbs in the back. it sounds like a cross feed.If the problem isn't there then i'd say the turn signal switch is bad.