All lights work, driving lights, turns, etc. Just no brakes.
I've checked the 2 fuses I think are related, marked yellow in photo.
I've checked the bulbs and they look fine.
I've replaced the brake switch behind the brake peddle.
We are getting 12v to that switch harness.
No OBDII errors.

So... what should I do next ya think, what am I missing on the jeep?

 

OBDII is useless for lighting problems.

Have you checked the sockets themselves, and the grounds?

The ground is behind the panel where your spare tire mounts. See my sig for a link to pictures of all the ground locations.

 

So you're getting regular dim red illumination but not the bright brake red?

Dumb question maybe but do they make a bulb that would fit that socket but not have double filaments?

Assuming its not that, I second checking the sockets themselves. Had one car where the rear sockets always ran hot and melted. Ended up putting in LED bulbs just to run cooler and not melt sockets.

 

true.
Well, I did take the two positive wires on the brake bulb (driving/brake) and swap them at the socket leads. Just to test the other filament. Works fine on either filament for driving lights. Meaning, good ground.
I also tested for V at the socket when brake is initiated. 0 volts when brake is depressed. I even took back the brake switch and got 'the most expensive one', still no go. Swapped out all 3 relative fuses even though they tested good.
Thanks though.

 

I guess what I'm actually looking for, is the path of power from the brake switch, to the bulbs. Not a wiring diagram. But the physical location of common breaks in this path.

 

This thing does have cruse control, which doesn't work. Don't care to make it work. But not sure if that matters.
No trailer hitch stuff.
Was working fine.

Recently I did:
- CB install
- New radio
- Rear hatch speakers
- Rear hatch LED
- Rear CB antenna.

None of these are even close to touching anything related to brake light circuit. All new wire ran for these.
((and yes, she will be all LED like my 79 soon))

 

the wiring harness for basically everything in the back starts by the passenger side door on the floor, then swaps sides underneath the back seat, goes back to the rear, up top on the c-pillar I believe, and then through to the hatch on the top drivers side through a grommet.

 

ffs..... it's fixed. thanks. and nv.

I was looking at the # of socket...... derp.
was a fuse.

Yesterday I drove home and when I had to stop, I pulled the light switch so red lights would be on lols.

 

Happens to the best of us man. I once spent three days chasing down an electrically based no start for it to end up being a bad ground.

 

try this, drivers side kick panel, there are a few plugs. One of them( I remember a big one) had worked its self loose. I plugged it is tight, and put a zip tie around it to hold it tight, than my break light worked. I had the same symptoms you have, and I would suggest separating the plugs, spray them to clean them, and plug them back up. It might help. Good luck.