What makes the Brake light come on?
Thread Starter
TECH Regular
Joined: May 2014
Posts: 440
Likes: 22
From: Houston Texas
What makes the Brake light come on? Im at a loss right now...
Ebrake switch is working properly at switch. Full on fluid. Brake lights are all good. Calipers are good, hub bearing/speed sensors are good.....
What else is there? Occasionally ABS INOP comes on, but haven't been able to diagnose it because code readers keep failing to connect unless light is off. But then fails to connect when trying to see code history.
What all triggers the BRAKE(P)(!) light to come on?
Ebrake switch is working properly at switch. Full on fluid. Brake lights are all good. Calipers are good, hub bearing/speed sensors are good.....
What else is there? Occasionally ABS INOP comes on, but haven't been able to diagnose it because code readers keep failing to connect unless light is off. But then fails to connect when trying to see code history.
What all triggers the BRAKE(P)(!) light to come on?
TECH Regular
Joined: Nov 2011
Posts: 471
Likes: 14
From: Tucker, GA
There is a sensor in the proportioning valve that will trip if something goes wrong in the brake circuit. Unless I am mistaken, it will latch in the tripped position until the issue has been fixed and the switch reset. There's also a way to test the switch-circuit itself, but I am not sure of the process.
What concerns me is you mentioning an occasional ABS light coming on. If were you I'd take the car to a reputable shop and have the car scanned. They may find potential codes in the abs module that could be causing your issues. A permanent red brake light coming on is a definite sign of something wrong especially when all other functions seem to be in working order.
OP,
How do you know all of what you mention is good w/out being able to complete scan? If the INOP light triggers while the car is in motion that usually leads to a bad wheel sensor.
How do you know all of what you mention is good w/out being able to complete scan? If the INOP light triggers while the car is in motion that usually leads to a bad wheel sensor.
Thread Starter
TECH Regular
Joined: May 2014
Posts: 440
Likes: 22
From: Houston Texas
Ive replaced both hub assemblies, SKF units. Initially, I was able to read codes in ABS module. After swapping hubs, I cleared the codes, and it stayed off for a bit. Brake light has NEVER gone off since I got the car. ABS Inop came back on, but I have not been able to read the codes. This is at my buddy's shop with his fancy shmancy Snap-On touch screen reader. Supposedly $6k, so I think that should do it, right?
I was able to get it to read once, but I forget exactly. I pressed back on accident, and then couldnt get back to it. Something about right side dump, or along those lines? Buddy suggested ABS module is going bad, will this trigger the Brake light, or only the ABS light? I havent found any replacements, or anyone to rebuild them in the event I need to replace it. What are my options there? Used would be too iffy I imagine, but might be only option.
Brakes feel fine, stop hard, and give me no feedback issues. Traction control kicks on if I stop hard on wet surfaces, Im just really ******* tired of that red light always on. ABS light is intermittent, and doesnt always come on. Ive gone a few days with it off. Hard to verify exactly when it comes on, but seems to be triggered during breaking if Im paying attention correctly. Goes off when I kill it, doesnt always come back on. Sometimes has come on right away.
Ive been thinking ABS and Brake light are mostly independent. I guess I need to know if they are or not. Thatll certainly narrow it down.
I was able to get it to read once, but I forget exactly. I pressed back on accident, and then couldnt get back to it. Something about right side dump, or along those lines? Buddy suggested ABS module is going bad, will this trigger the Brake light, or only the ABS light? I havent found any replacements, or anyone to rebuild them in the event I need to replace it. What are my options there? Used would be too iffy I imagine, but might be only option.
Brakes feel fine, stop hard, and give me no feedback issues. Traction control kicks on if I stop hard on wet surfaces, Im just really ******* tired of that red light always on. ABS light is intermittent, and doesnt always come on. Ive gone a few days with it off. Hard to verify exactly when it comes on, but seems to be triggered during breaking if Im paying attention correctly. Goes off when I kill it, doesnt always come back on. Sometimes has come on right away.
Ive been thinking ABS and Brake light are mostly independent. I guess I need to know if they are or not. Thatll certainly narrow it down.
All I know is when the ABS module is turned on it does a system scan. If the light turns on immediately after starting the car then it could be something upstream from the wheel sensors. If the light turns on after the car is in motion then most likely it's a wheel sensor.
I haven't had ABS on mine since 1999 when I went with a 12-bolt. ABS light still works!
I haven't had ABS on mine since 1999 when I went with a 12-bolt. ABS light still works!
Thread Starter
TECH Regular
Joined: May 2014
Posts: 440
Likes: 22
From: Houston Texas
IS there a way to test the speed sensors? Or simply replace and cross fingers? I dont think it was wheel speed sensor, but I cant say 100%. I do know, there was only one code that came on AFTER I did the work and cleared everything. And it wasnt speed sensor, something about dump check valve or some ****. I started a thread while back going over everything. Thats when I last cleared/checked the codes.
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TECH Regular
Joined: May 2014
Posts: 440
Likes: 22
From: Houston Texas
Im ready to just do away with the ABS altogether. But, I like fixing **** right, so Im just hesitant. I dont need ABS or traction control. But I want the lights off. Im gonna poke around some more this weekend, Im not really driving it until I send the PCM off to get tuned, running rough and wanna get a few more things checked off the list.
Gonna go look at different methods of bypassing the ABS stuff.
Gonna go look at different methods of bypassing the ABS stuff.
Teching In
Joined: Feb 2013
Posts: 14
Likes: 1
From: Connecticut
Checked my 95 F-car FSM and the only things shown commanding the red brake warning light were parking brake, combo valve, ABS module, and oddly a fault in hatch release wiring for manual trans cars. Also, something associated with daytime running light module. These all can turn on light by completing a circuit to ground, so easy to test which it is by disconnecting one at a time or checking for a short to ground.
For the ABS module, there are something like 20 codes that will light the red warning lamp. None are associated with the wheel speed sensors. ABS control module itself, ABS enable relay/wiring, or the actual ABS motors/solenoids or wiring. Hopefully you can pull the codes.
Hope this helps -
Jim
For the ABS module, there are something like 20 codes that will light the red warning lamp. None are associated with the wheel speed sensors. ABS control module itself, ABS enable relay/wiring, or the actual ABS motors/solenoids or wiring. Hopefully you can pull the codes.
Hope this helps -
Jim
Thread Starter
TECH Regular
Joined: May 2014
Posts: 440
Likes: 22
From: Houston Texas
Checked my 95 F-car FSM and the only things shown commanding the red brake warning light were parking brake, combo valve, ABS module, and oddly a fault in hatch release wiring for manual trans cars. Also, something associated with daytime running light module. These all can turn on light by completing a circuit to ground, so easy to test which it is by disconnecting one at a time or checking for a short to ground.
For the ABS module, there are something like 20 codes that will light the red warning lamp. None are associated with the wheel speed sensors. ABS control module itself, ABS enable relay/wiring, or the actual ABS motors/solenoids or wiring. Hopefully you can pull the codes.
Hope this helps -
Jim
For the ABS module, there are something like 20 codes that will light the red warning lamp. None are associated with the wheel speed sensors. ABS control module itself, ABS enable relay/wiring, or the actual ABS motors/solenoids or wiring. Hopefully you can pull the codes.
Hope this helps -
Jim
Thanks for that guys. Gonna poke around see if i can find any shorts. Now, all my lights dim when i hit the brakes. Was thinking about doing Big 3, but really need to verify if any shorts present. I haven't seen anything yet, but haven't specifically searched yet.
They had wired in a flasher setup for the rear brakes to blink like the mustangs when blinker is on. Was a **** job, but i put everything back to stock and didn't have any other issues. Maybe something happened..
My rear hatch works, are these supposed to pull it down like the later 3rd gens? It doesn't do that. I gotta hit the button a couple times and pull up onnit.
That's because on manual cars, the hatch release won't work unless the E-brake is pulled, which creates a ground for the hatch release relay.
"The red "BRAKE" warning lamp will be illuminated when a low brake fluid level in the master cylinder is sensed, the parking brake switch is closed, or under control of the EBCM when certain ABS codes are set. This lamp indicates to the driver a base brake problem may exist." - Out of the service manual. 93-97 cars don't have a low level sensor, so don't bother looking for one.
I've gone to O'Reilly to borrow their ABS scanner before, see if yours will let you do that. Some ABS scanners don't work on our ABS system because it's so old and finnicky, just something to keep in mind. You can also buy a cheap ABS scanner off the interwebs, just make sure they say it will work with our cars.
"The red "BRAKE" warning lamp will be illuminated when a low brake fluid level in the master cylinder is sensed, the parking brake switch is closed, or under control of the EBCM when certain ABS codes are set. This lamp indicates to the driver a base brake problem may exist." - Out of the service manual. 93-97 cars don't have a low level sensor, so don't bother looking for one.
I've gone to O'Reilly to borrow their ABS scanner before, see if yours will let you do that. Some ABS scanners don't work on our ABS system because it's so old and finnicky, just something to keep in mind. You can also buy a cheap ABS scanner off the interwebs, just make sure they say it will work with our cars.