'96 XJ here and I've just replaced everything you can on my rear drum brakes, and now that they're done the red 'BRAKE' dash light is constantly on. I have sort of an idea as to why but no idea how to go about fixing it. This happened on both sides btw... When I had finished replacing everything and was fitting the new drum around the new pads neither drum on either side would slide on. Somehow the shoes were too far apart by just a hair. Looking back, I now know what happened to cause this, just wish I had realized it then. When I began installing the new parts the first thing I put in on both sides was the new wheel cylinder and attached the brake lines. I think when I attached the brake lines it kept some pressure in the cylinder and they wouldn't let the top of the brake shoes retract in as much as they should've. To correct this I should've cracked the bleeder valve and left it open until everything was fit back together.

So what does my dumb a$$ do...is I take the adjuster wheels back out (where the bottom of the brake shoes rest) and dremel grind both ends down some so the shoes can come together a bit more. This was enough for the drums to go on and voila! job done. Yep, not so much.

How do I go about adjusting things so my dash brake light goes off? Only thing I know to do is to get new adjuster wheels and redo the build steps again with the brake fluid bleeder valve cracked open, close it all up, bleed the lines and see if that gets the light off.

One thing I should mention that could be a factor here is that when I took off both drums there was the same piece broken in each one...the odd cable part that hooks onto the thick top anchor point where the top two shoe springs attach, does a 90 deg turn around another piece to the side then continues down to hook into the odd J looking piece close to the bottom adjustment wheel. I think this part has something to do with the emergency brake but I'm not entirely sure. The green line in pic below shows where each of these pieces/cables were broken. The pic isn't of my brakes, just one I pulled off the net.

 

Do you have ABS ? I understand ABS have bleeding issues

Check the FSM to see what triggers the brake light, it could be the proportioning valve, ABS, or the fluid switch in the bottle

Once you have a better idea of what triggers it, you can take apart the relevant items, bleed and hope.

Does it have a good firm pedal now ?

The snapped cable is part of the "auto adjust" mechanism. It is fairly common to find these parts, damaged or seized
You didnt say how much you ground of adjusters, if only a little, probably ok, if more than say 1/8" would be undesirable imo

 

So far as I know that light is only an e-brake on/low fluid warning, even with ABS, which has its own warning light for faults within that system.

 

RED BRAKE WARNING LAMP
The red brake warning light will illuminate under
the following conditions:
• 2-3 seconds at start-up as part of normal bulb
check.
• When parking brakes are applied.
• Low brake pedal caused by leak in front /rear brake hydraulic circuit .
If the red light remains on after start-up, first verify that the parking brakes are fully released. Then
check pedal action and fluid level. A red light plus low pedal indicates the pressure differential switch
and valve have been actuated due to a system leak.
On models with ABS brakes, the amber warning light only illuminates when an ABS malfunction has
occurred. The ABS light operates independently of the red warning light.