Brake Warning Light

[bam_bam1ca]

Good evening.

I am experiencing an intermittant problem with my brake warning light. The dash light will turn on intermittantly and go out. I have checked the fluid level in the master, and it is full. The pedal is firm and does not bleed down. The brakes and anti-lock system are also working fine. I have not touched the emergencies, so I am not suspecting that switch. Sometimes the lamp will come on bright, and other times it will be dim, or dim and flickering. This sounds like it may possibly be a ground problem. Has anybody else experienced this problem?

 

[gluvsave35]

i see u said u checked the level in the master,,, but did u check the float in the master??? sometimes they get stuck down...

 

[budwich]

As you outlined, there are the two conditions. With your symptoms, it is likely a fliud level issue which could be related to a bad fluid "switch". Easiest way to isolate would be to disconnect the wire coming from the fluid system and see if the problem goes away. As for fix, not sure whether its a full replacement or just the part.

 

[bam_bam1ca]

Fluid is up, and I poked the level indicator float a couple of times to make sure it wasn't stuck. Then I disconnected the harness for the level indicator, but no change. I also disconnected the wire for the over-travel switch that indcates the master piston has travelled too far, but nothing.

 

[budwich]

That's great info. Basically, that means (I think) that your problem lies with the "other circuit"... that being the emergency brake since the two circuits lie in "parallel". As you have done, you can take the connector off at the e brake switch to see if that has any change but also after looking at my 96 drawings there is one other "suspect". Do you have DRLs (day time lights)??? If so then there is a possibility that the module / connector there is causing you problem as it is in the ebrake circuit.

 

[adam4584]

there's actually another part that could be the problem. the proportioning valve (i think thats the one) has a little sensor that tells you if your front or rear brakes aren't working. i have no idea where it's at but it shouldn't be too hard to find.

 

[bam_bam1ca]

Ya, I do have DRL, and also noticed the module on the schematics as a possible source of the fault. Now the million dollar question, where is the module located???? I take it buried a mile up under the dash behind several sharp objects. :

I have noticed that it is temperature related also. Yesterday it was warm and the light flickered on and off a few times. Today it is well below freezing again and it has been off all day.

I put the OBDII scanner on today, and there weren't any stored codes (go figure).

I am thinking that it might be a valuable exercise to bleed the brake system so that I have fresh fluid which might help if it was a sludged up switch, or a sticky proportioning valve. Does anybody have experience doing bleeding for preventive maintenance? Can I just bleed the system as "normal", or should I be using a breakout box to activate the ABS system and flush that as well?

 

[bam_bam1ca]

God I LOVE this site!!!

http://www.explorerforum.com/forums/showthread.php?p=1243238

Picture in another thread of the DRL module on the driver's side frame rail looking from the wheel well.

Judging from where it is located, this looks like a nightmare for corrosion (read bad ground) from the bracket to the frame.

 

[budwich]

I think that if you unplugged the connection from the master and it had no effect then doing anything else at the master isn't going to help with your problem other than give you "piece of mind"... which is OK. In terms of bleeding though be careful not to let air into the system by mistake / accident as ABS systems require a special tool / capability to "clean up" if you cause yourself problems. I think you are on the right track with the DRL stuff so good luck. Remember a meter is your friend.

 

[ericjames525]

I am having a very similar problem. The brake light on my dash glows dim whenever the car is turned on. I have tried unplugging the sensor on the emergency brake, as well as the fluid level and pressure sensor on the reservoir. None of these had any effect on the glowing. If I engage the ebrake or push down the fluid sensors, the light gets brighter so I know its working correctly.

I do not have daytime running lights, so I know thats not the problem.

I assume it has to be electrical, but I have no clue where to start looking... does anyone have any advice?

Thanks