Red BRAKE Light

[Dirt J]

Is it only controlled by the parking brake switch? I'm sure this information is on here somewhere or in the FSM...

 

[Dirt J]

Apparently this light is controlled by fluid level sensor AND parking brake sensor.

It is illuminating intermittently. Trying to diagnose.

 

[squidmotion]

Maybe this is the answer:

After replacing my master cylinder assembly, i noticed that the brake lights were on continuously. I then noticed a few odd looking small pieces of broken, amber plastic on my floor mat.

As it turns out, there is a tiny clip that rides on the pedal, under where the switch is activated. With this gone, all of a sudden the brake light was on all the time, as the piece wasn’t there to turn it off. I diagnosed by using a small screwdriver on the switch, whilst my wife yelled at me from behind the truck. I searched Partsouq for the number, but had not luck (i’m sure there is a number for this little joker)

I did what any decent DIY dude would do, I used a zip tie there, snugged up hard in the spot where that plastic spacer/clip used to be. It’s been working fine for a while now, but I would like to have the original part.

I saved the broken pieces, i’ll try to remember to get a photo tomorrow.

EDIT:

I just realized you were talking about the brake warning light on the dash, not the brake lights themselves.

In this situation, I would make sure you don’t have too much fluid, as that will make the light come on (easy mistake, and i’m sure you already know this.. but it’s made by many, because of the process for checking the fluid is different than most other vehicles).. . for those who don’t know, it’s printed on the MC… ignition off, 40 pumps or so, till the pedal goes soft, then see where the fluid is.

Also, check the fluid on a level surface. if it’s a bit low, it will cause the intermittent light.

Also look for leaks. No such thing as a minor brake leak.

Also, check the switch on the ebrake handle.

Also, the level switch on the master cylinder has been know to go bad sometimes.

If you have a good code reader, that can read airbag and brake codes, see if you have a code. It might be wheel sensor, but i believe that would make the ABS warning light illuminate as well.



I would also pray that the ABS light doesn’t come on in a few days.

 

[Dirt J]

Also, check the fluid on a level surface. if it’s a bit low, it will cause the intermittent light.

It appears this was the issue. Apparently the fluid was just low enough that it would occasionally trigger the BRAKE light.

After the 40-pump procedure, it was just a bit under halfway between MIN and MAX. I topped it off this morning to MAX after the 40-pumps, and it did not illuminate on my commute like has the past few days.

Side note: I replaced the entire brake booster assembly not too many miles ago, so that should not be it. Can't recall if I filled it to MAX or just in the area between MIN and MAX. Guessing/hoping it just needed topping off due to brake pad wear (i.e. more fluid in the lines, less in the reservoir where the fluid level sensor is.)

Reading the FSM shows the job of the red BRAKE light is to either warn of parking brake being engaged or low fluid level. Orange ABS light is the "bad" one that points to ABS system issues.