Brake light ... What is the order of operation to correct.

[StayAtHomeDad]

I have searched, read, and come to understand @mrblaine is the brake expert (and maker of BMB and other jeep components?). I can't seem to tag him, but would like to resolve the issue with my brake light staying on.

I am aware that it signifies that the shuttle has moved in the proportioning valve due to detected uneven pressure. I have attempted stomping the brake pedal.

The TJ came with new brake lines, and the brake light on. I have since replaced all other brake components bled the brakes to clean fluid, activated ABS with scanner, and bled the brakes again. Clean fluid at all corners, but brake light is still on. Pedal feels great, truck generally stops great but will lock the rear wheels quite easily, and the dash brake light is still on.

What is my next step to solving this issue?

After less than 150 miles on the new brake system there is no sign of leaking. I visually check wheel cylinders, calipers, rear proportioning valve, and master cylinder and placed dry towel under each component and connection while it sat In garage, the reservoir isn't losing fluid, and everything seems to functioning properly, but I can't get the brake light to turn off (unless I unplug it).

My abs light is also on, but the scan tool seemingly gets the module to function, but while driving it does not function. I would have to double check the actual code that comes up, but I am hoping that wouldn't affect the brake light.

 

[StayAtHomeDad]

In case it wasn't clear, the brake light on the dash was on during all bleeding procedures, and I was able to get fluid to all bleeder screws, and although everything was done alone, through the use of a camera, I was able to determine that pressing the brake pedal does indeed activate each caliper piston, or wheel cylinder pistons.

 

[P man]

You tagged him correctly..he will get on at some point and answer you. You can always send him a message as well.

 

[mrblaine]

In case it wasn't clear, the brake light on the dash was on during all bleeding procedures, and I was able to get fluid to all bleeder screws, and although everything was done alone, through the use of a camera, I was able to determine that pressing the brake pedal does indeed activate each caliper piston, or wheel cylinder pistons.

Manually shift it is the only thing left. You'll have to pull the block, peek in the hole where the switch screws in, and then move the shuttle until you see the detent the plunger rides in.

 

[StayAtHomeDad]

Manually shift it is the only thing left. You'll have to pull the block, peek in the hole where the switch screws in, and then move the shuttle until you see the detent the plunger rides in.

Thank you. I chose this method rather than private message to hopefully help any others, as I wasn't able to find the answer by searching.

To be clear, when you say "pull the block",do you mean remove the combination block from the vehicle, then remove the switch and attempt to slide the shuttle with a small tool (screwdriver?), ultimately leading to bleeding all brakes again?

 

[StayAtHomeDad]

I am still interested in learning what is actually happening.

Because I know fluid is still traveling all appropriate routes, is the purpose of the shuttle in the combination block just to limit (not stop) the fluid travel when the pressure differential is present?

For example, in my scenario, it seems the rear is getting more pressure. So at some point, the Tj potentially had a leak in the front, and the shuttle moved to correct this. It never stopped sending fluid to the front but just limited the amount of fluid or pressure allowed in that direction?

So if I don't correct this, all my brakes will function, but I will maintain the rear bias pressure? (I do intend to correct this, just trying to understand)

 

[mrblaine]

Thank you. I chose this method rather than private message to hopefully help any others, as I wasn't able to find the answer by searching.

To be clear, when you say "pull the block",do you mean remove the combination block from the vehicle, then remove the switch and attempt to slide the shuttle with a small tool (screwdriver?), ultimately leading to bleeding all brakes again?

Yes, but just remove the port adapter on the back at the booster side. You can pull it out with some skinny needlenose pliers. Yes, you will have to bleed again.

 

[mrblaine]

I am still interested in learning what is actually happening.

Because I know fluid is still traveling all appropriate routes, is the purpose of the shuttle in the combination block just to limit (not stop) the fluid travel when the pressure differential is present?

For example, in my scenario, it seems the rear is getting more pressure. So at some point, the Tj potentially had a leak in the front, and the shuttle moved to correct this. It never stopped sending fluid to the front but just limited the amount of fluid or pressure allowed in that direction?

So if I don't correct this, all my brakes will function, but I will maintain the rear bias pressure? (I do intend to correct this, just trying to understand)

Yes, sometimes it doesn't shift all the way and you get the reduction in flow you with a higher rear bias.