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View Full Version : Air bag light, security light, and brake light?


Socom
11-09-2013, 02:42 PM
I've been trying to chase down why some lights are on my dash but I can't seem to figure them out. My car is a 97 Z28 for reference. One day after cruising, my air bag light came on as I parked and hasn't gone out since. I also have a security light on and my e-brake light doesn't go out when I put the e-brake down. Are they all tied together somehow? Prior to to the air bag light coming on I could arm my security system with my key fob and the red light under the dash pad would blink, but now when I arm it the horn honks like normal, but no light. I do believe the BCM has been replaced before so maybe that has something to do with it. Any ideas?
popo8
11-10-2013, 01:44 PM
As a quick test...top off ur brake fluid and see if the brake light stays on.

MEMBER @ LTXtech.com
Injuneer
11-11-2013, 04:13 PM
The "BRAKE" light has two functions - 1) to tell you the e-brake is on; 2) to tell you there is a pressure imbalance between the front and rear braking systems. It does not come on because the brake fluid is low, unless it's so low that you are getting air in the hydraulic system, affecting the pressure (soft pedal).

The alarm system, and the PASS-Key system are controlled by the BCM, and the BCM is interfaced with the ABS diagnostic system which includes the BRAKE light. So it could all be due to a BCM printed circuit board problem, or a shared ground.

The air bag system seems to have it's own controller, with no interface to the BCM.The Tech-2 can pull codes on all these systems. GaryDougs OBD-1 scanner can as well, but I don't know if his OBD-2 scan software can do it.
popo8
11-11-2013, 04:29 PM
mine comes on any time my pads are low... topping off the fluid kills the light till i put new pads on.

MEMBER @ LTXtech.com
Injuneer
11-11-2013, 05:53 PM
The light is activated by a switch on the block of the side of the ABS unit, where the lines from the master cylinder attach. Higher pressure on one side pushes the switch off center and the light comes on. It will also come on when some of the ABS codes set. Not sure how it would know your pads are worn or the fluid is low, but if if works for you, just keep doing it.
popo8
11-11-2013, 06:10 PM
The light is activated by a switch on the block of the side of the ABS unit, where the lines from the master cylinder attach. Higher pressure on one side pushes the switch off center and the light comes on. It will also come on when some of the ABS codes set. Not sure how it would know your pads are worn or the fluid is low, but if if works for you, just keep doing it.

IDK.... just reporting.
Socom
11-13-2013, 03:20 PM
Well I have ABS, ASR, and cruise control deleted, so thats probably why the brake light is on :P My twilight sensor still activates the headlights when I put my e-brake down so its functioning properly. I have VATS disabled through my tune but my alarm still "arms" when I press my lock button on my key fob twice, but doesn't go off. I replaced my BCM since I was having the issue with windows and radio cutting in and out, would this cause the issue? Is there a way to disable it through the resistor trick if I do not have the key from the car at the junk yard I got the BCM from?