Brake and ABS light?

[NeXtras]

The other day i started my truck and my E brake light stayed on, which it shouldnt, pedal fully up, and its not even connected, no cables in it right now.. along with the ebrake, the abs light would come on.. both are on steady and wont go away.. sometimes the brake light will go off but the ABS light stays on.... i cant figure out whats going on.. anything to do with no cable attaced in the pedal... the sensor IS hooked up

 

[TexasNomad]

Well the Ebreak might just be a failing switch nothing big there.
now the abs might be some thing more serious (maybe) it could be some thing in the computer or some thing physical you need to change out. i've never had any break related issue with my bronco so maybe some one else can help you out...

 

[john112deere]

Check the fluid level in your MC?

I don't know much about ABS (not even sure if your truck has 2w or 4w ABS), but if the fluid in the master drops far enough, it'll light the same light on the dash as setting the e-brake.

 

[CowboyBilly9Mile]

If it's like a 94 Ranger, you can pull RABS codes; that's probably where I'd start.

 

[NeXtras]

my trucks RABS... brake light comes on BEFORE ABS... so i assume something switch related

 

[CowboyBilly9Mile]

I had a similar problem where both the brake and ABS lights would come on when pushing hard on the brake and the lights stayed on until the next duty cycle, followed by a hard brake application. I solved that problem by doing a thorough flush on the system. It was a permanent fix. But before doing that I'd pull codes. I also assume that your switch and associated wiring are not grounded, causing the steady brake light.

*Don't ask my why, but that brake and ABS light were somehow related; I was a bit surprised and caught off guard. Also, Ian gave good advice too.

 

[NeXtras]

well if the truck senses the ebrake on, abs isnt going to work because it cant pulse the pads cause there locked

 

[CowboyBilly9Mile]

That ABS code just could have a story to tell

If it's like a 94 Ranger, you don't need a scanner to pull it, just a jumper wire and maybe five minutes of time.

 

[d-kuzmen]

The Red brake light and abs light are related. You need to pull codes on the rabs module. The red light on will cause the abs light. Most common problem is the float assembly in the master. Heres the procedure to pull codes as well as a PPT for the red light on.

Retrieving Diagnostic Trouble Codes (DTC)


NOTE: Verify the ignition switch (11572) is in the RUN position (engine does not need to be running). Next, locate the black RABS II diagnostic connector. The diagnostic connector has two mating halves (one of which has a black/orange wire connected to it). Disconnect the two halves.

Attach one end of a jumper wire to the black with orange stripe wire side of the diagnostic connector. Momentarily ground the opposite end of the jumper wire by connecting it to a good chassis ground for 1-2 seconds. Grounding this wire should start the REAR ABS lamp flashing. If grounding this wire does not start the REAR ABS lamp flashing, go to System Pre-Check Test D, Yellow REAR ABS Light Self-check OK, but no diagnostic trouble code when diagnostics are started.

CAUTION: Care must be taken to connect only the black/orange stripe wire to ground. Connecting the mating connector wire to ground will result in a blown fuse.

The code consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. For example, three short flashes followed by one long flash indicates diagnostic trouble Code 4. The code will continue to repeat itself until the key is turned off. It is recommended that the code be verified by reading it several times. This code will be used later for system repair instructions. It should be written down for future use. A diagnostic trouble code of 16 will be obtained when the anti-lock electronic control unit detects normal system operation.

Component Location, F-150-250-350
The RABS II consists of the following components:

Anti-lock electronic control unit located in the cab directly behind the glove box.
Anti-lock brake control module (dual solenoid electro-hydraulic valve) located on the left frame side rail (5015) just behind the No. 1 crossmember.
RABS II speed sensor and speed sensor ring located in the rear axle carrier.
Yellow REAR ABS warning light in the instrument cluster.
RABS II diagnostic connector located in the cab and clipped on the main instrument panel wiring harness about three inches below and to the right of the anti-lock electronic control unit .
Diode/resistor element located under the power distribution box.
Sensor test connector with cap located under the hood on the left wheel well.






SYSTEM PRE-CHECK TEST E — RED BRAKE LIGHT ON
System Pre-Check Test E, Red BRAKE Light ON When Key in RUN Position
Affected Circuit(s)/Electrical Component(s)





Description
Red BRAKE light ON with ignition switch ON and parking brake released.

Possible Contributing Base Brake Component/Vehicle Wiring Concerns
Brake fluid level low in brake master cylinder
Wiring between diode/resistor network and anti-lock electronic control unit is shorted to ground
Anti-lock electronic control unit module
Worn or damaged brake fluid level switch

E1 PULL CODE
Pull code.
Is code 4 obtained?
Yes
RECONNECT data link connector and KAM connector. GO to Pinpoint Test — Code 4.

No, no code is obtained
GO to System Pre-Check Test D.

No, code is not code 4
GO to E2 .


E2 CHECK BRAKE FLUID LEVEL IN MASTER CYLINDER
Check the brake fluid level at the brake master cylinder reservoir .
Is the fluid level within specification?
Yes
GO to E3 .

No
CHECK for leaks in the vehicle brake system and REPAIR as required. FILL the brake master cylinder reservoir to the required level. REPEAT E1 .


E3 VERIFY FLOAT BUOYANCY
Remove the brake master cylinder filler cap from the brake master cylinder reservoir .
Using a clean steel implement, attempt to push the float down.
Does the float move down?
Yes
GO to E4 .

No, the float sits on the bottom
REPLACE the brake master cylinder reservoir . BLEED the brake system. REPEAT E1 .


E4 CHECK ANTI-LOCK ELECTRONIC CONTROL UNIT
Key OFF.
Disconnect RABS II module harness connector.
Key ON.
Does the red BRAKE light turn on?
Yes
RECONNECT RABS II module connector. GO to E5 .

No
REPLACE anti-lock electronic control unit . RECONNECT RABS II module connector. REPEAT E1 .


E5 LOCATE CAUSE OF RED BRAKE LIGHT ON
Key OFF.
Disconnect the fluid level switch harness connector from the brake master cylinder .
Key ON.
Does the red BRAKE light turn on?
Yes
Diesel only: GO to E6 . All others: GO to E7 .

No
GO to E8 .


E6 LOW VACUUM SWITCH CHECK (DIESEL ONLY)
Key OFF.
Disconnect low vacuum switch harness connector.
Key ON.
Does the red BRAKE light turn on?
Yes
GO to E7 .

No
RECONNECT all loose connections. REFER to Section 06-07B to diagnose reason for Low Vacuum Switch actuating the red BRAKE light.


E7 PARKING BRAKE SWITCH
Key OFF.
Disconnect parking brake switch harness connector.
Key ON.
Does the red BRAKE light turn on?
Yes
LOCATE and SERVICE short to ground in Circuit 977(P/W), 640(R/Y), 531(DG/Y), or 162(LG/R). RECONNECT all loose connections. REPEAT E1 .

No
REPLACE parking brake switch. RECONNECT all loose connections. REPEAT E1 .


E8 CHECK FLUID LEVEL SWITCH
Key OFF.
With the fluid level switch harness connector disconnected, jumper between Circuits 512(T/LG) and 531(DG/Y).
Key ON.
Does the red BRAKE light turn on?





Yes
LOCATE and SERVICE short to ground in Circuit 512(T/LG). RECONNECT all loose connections. REPEAT E1 .

No
REPLACE brake master cylinder reservoir . BLEED brake system. RECONNECT all loose connections. REPEAT E1 .


INTERMITTENT DIAGNOSIS PROCEDURE

 

[NeXtras]

ill try that procedure tomorow thanks..

i just topped off the MC, was a tad low.. we'll see what happens..