How's the brake fluid level?

 

How are the axle shafts?

 

From the primitive inspection I was able to do in the hotel garage, the brake fluid seems untouched, perfect level. Felt around the inside of the wheels, no sign of fluid. After I made this original post (I just got back from driving around in the mountains) I went back downstairs to the garage and checked the above. After completing the check, I started the Jeep, no light. The garage is heated. It seems that after driving around in the cold, the light comes on. This did not happen back home at all (much warmer in NJ than here in Quebec (7F) and the salt here is insane. My Jeep looks white now. It really seems like there is a "bridge" on the sensor of salt/water, I just wanted to know if it is possible that the light is being tripped by any of this.

 

After another day of driving/parking, it seems when the jeep warms up, the problem goes away. As soon as I drive for 10/15 minutes in the arctic chill, the light comes on. I know bringing it to the dealer is pointless since they won't do squat because they can't replicate the problem. I guess I will wait until I get to Jersey and see if the problem goes away....although I don't like the fact that this light will come on everytime I am in a cold climate.

 

After another day of driving/parking, it seems when the jeep warms up, the problem goes away. As soon as I drive for 10/15 minutes in the arctic chill, the light comes on. I know bringing it to the dealer is pointless since they won't do squat because they can't replicate the problem. I guess I will wait until I get to Jersey and see if the problem goes away....although I don't like the fact that this light will come on everytime I am in a cold climate.

Just a thought... Have you taken it to a car wash and power washed underneath?

 

My last jeep did that.
I needed wheel speed sensors and a cleaned out hub because the sensor broke off into the hub. It was a mess.

 

No, no wash. I washed the jeep at home before I left and then drove 600 miles to quebec. Thats where the problem started. Jeep is currently covered in salt and slop (slush) which melts off in the garage. My suspicion is the salt is doing something with the sensor, but who knows.

As for wheel speed sensors, I believe other symptoms would arise, including a malfunctioning ESP no?

 

The brake fluid viscosity is changing in the COLD cold weather. It warms up and returns to it's natural state. Try insulating the reservior.

Bob K.

 

This would be odd since the reservoir is under the hood, so the longer I drive it seems the warmer it gets (unless the fluid in the outside lines is getting supercooled quickly.)

I still suspect it is a salt/water issue messing around with the sensor. Anyone know where the sensor is located that feeds the BRAKE light on the dash? I may clean it thoroughly when I get home, and throw a few coats of plastidip on there to protect it.

 

It brake fluid isn't changing. It's more a salt issue. I drive mine daily and it's been in the negatives in temps.

 

Wheel speed sensors will impact ESP and BAS triggers before the brakes. Could be salt/debris in the rear drumheads? I mentioned the brake fluid viscosity from my experience in Ft. Greely AK.

Bob K.

 

DESCRIPTION 07-09 JK





The park brake switch (1) is located on the park brake lever mechanism on the floor panel transmission tunnel below the center floor console. This switch includes a spade-type output terminal (2) that connects the switch to the vehicle electrical system through a dedicated take out and connector of the instrument panel wire harness. The output terminal is integral to the stationary contact within a molded plastic insulator. A locating tab (4) on the insulator engages a slot in the park brake lever mechanism for positive switch location. External to the insulator is a movable leaf contact (3) with an integral grounding lug on one end and an integral actuating lever and follower on the opposite end. The switch is secured to and grounded by a single screw to the park brake lever mechanism.
The park brake switch cannot be adjusted or repaired and, if ineffective or damaged, it must be replaced.

 

Have an appointment at the dealer on friday. Will report back.

 

I had something similar happen on a 98 CRV when cold, I think my float may have been stuck and was slightly under the fill line but when I added fluid it was deceptive as i needed to pour in more than i thought i would have just to get back to that fill line. problem never came back

this is from the 2012 OM, being under warranty I would take it in too!

274 UNDERSTANDING YOUR INSTRUMENT PANEL
11. Brake Warning Light
This light monitors various brake functions, including brake fluid level and parking brake application. If the brake light turns on it may indicate that the parking brake is applied, that
the brake fluid level is low, or that there is a problem with the anti-lock brake system reservoir.
If the light remains on when the parking brake has been disengaged, and the fluid level is at the full mark on the master cylinder reservoir, it indicates a possible brake hydraulic system malfunction or that a problem with the Brake Booster has been detected by the Anti-Lock Brake System (ABS) / Electronic Stability Control (ESC) system. In this case, the light will remain on until the condition has been corrected. If the problem is related to the brake booster, the ABS pump will run when applying the brake and a brake pedal pulsation may be felt during each stop.
The dual brake system provides a reserve braking capac- ity in the event of a failure to a portion of the hydraulic system. A leak in either half of the dual brake system is indicated by the Brake Warning Light, which will turn on when the brake fluid level in the master cylinder has dropped below a specified level.
The light will remain on until the cause is corrected.
NOTE: The light may flash momentarily during sharp cornering maneuvers, which change fluid level condi- tions. The vehicle should have service performed, and the brake fluid level checked.
If brake failure is indicated, immediate repair is neces- sary.
WARNING!
Driving a vehicle with the red brake light on is dangerous. Part of the brake system may have failed. It will take longer to stop the vehicle. You could have a collision. Have the vehicle checked immediately.
Vehicles equipped with the Anti-Lock Brake System (ABS), are also equipped with Electronic Brake Force Distribution (EBD). In the event of an EBD failure, the Brake Warning Light will turn on along with the ABS Light. Immediate repair to the ABS system is required.
Operation of the Brake Warning Light can be checked by turning the ignition switch from the OFF position to the ON/RUN position. The light should illuminate for ap- proximately two seconds. The light should then turn off unless the parking brake is applied or a brake fault is detected. If the light does not illuminate, have the light inspected by an authorized dealer.
UNDERSTANDING YOUR INSTRUMENT PANEL 275
The light also will turn on when the parking brake is applied with the ignition switch in the ON/RUN posi- tion.
NOTE: This light shows only that the parking brake is applied. It does not show the degree of brake application.
12. Anti-Lock Brake (ABS) Light
After the ignition is turned on, the Anti-Lock
Brake System (ABS) light illuminates to indicate function check at vehicle start-up. If the light remains on after start-up or comes on and stays on at road speeds, it may indicate that the ABS has detected a malfunction or has become inoperative. The system reverts to standard non-anti-lock brakes.
If both the Brake Warning Light and the ABS Warning Light are on, see an authorized dealer immediately. Refer to “Anti-Lock Brake System” in “Starting And Operat- ing”.

 

The good thing is, by law, once the Jeep goes in on Friday, the dealer cannot release it to me without the problem being fixed, so no run arounds are to be had. I even have a photo of me doing 70 with the light on. It may very well be the fluid level (although it looks full with the level at the max line) but let them deal with it.

 

Video the error. My jeep dealer accepted my videos in place of being able to recreate issues.

 

Problems with the battery or charging system will also cause the brake light and abs light to potentially come on. Found this out this past weekend when my brake light and abs light would flash at me, and it turned out it was my dead battery causing the alternator voltage to go too high at times and causing an over voltage. Just throwing out this information, doesn't seem like it is the case here, but if you start having to hunt things down...

 

Video the error. My jeep dealer accepted my videos in place of being able to recreate issues.

I have a photo of me doing 70 with the brake light illuminated not video. I can make a video on my way to the dealer.

 

Problems with the battery or charging system will also cause the brake light and abs light to potentially come on. Found this out this past weekend when my brake light and abs light would flash at me, and it turned out it was my dead battery causing the alternator voltage to go too high at times and causing an over voltage. Just throwing out this information, doesn't seem like it is the case here, but if you start having to hunt things down...

Definitely not the battery. Jeep starts instantly but good to know. Also, no issues with abs or braking.

 

did you figure this out? I'm having the same issue.

 

Yes I did. It was my fault. After I installed the air compressor on the master cylinder, I didn't re-route the harness/wire that plugs into the reservoir, so it was getting pulled slightly. Unplug that harness, move the wiring so that it isn't stretched out, and plug it back in securely. Start the engine, and it will go away. It takes about 10 seconds to register that it is reconnected. Let me know if you need any other help.