Parking Brake light backwards!!!

I just had a new little problem today... The dashboard light for the parking brake is all of a sudden working backwards... With the parking brake engaged the light is OFF... When I release the brake the light turns ON... It's worked properly for over 2 years until today... The brake definately releases in spite of the ON light and definately engages in spite of the OFF light... In fact, if I engage the brake while in DRIVE the warning chimes start... But the light turns OFF when engaged and ON when released... What the heck would cause this???!!!

I just checked with a volt/ohm meter... With the parking braked engaged the two switch contacts are closed and read 0 Ohms to ground (0 volts across them)... With the parking brake released the switch contacts are open and there is 12 volts from ground to the green wire connected to the one side of the switch... Is this correct?... The brake light on the dash is still operating backwards...

I just checked with a volt/ohm meter... With the parking braked engaged the two switch contacts are closed and read 0 Ohms to ground (0 volts across them)... With the parking brake released the switch contacts are open and there is 12 volts from ground to the green wire connected to the one side of the switch... Is this correct?... The brake light on the dash is still operating backwards...

The light at the IP always has 12v at one side therefore, to illuminate the lamp it takes a ground or low.

Do you have a GM service manual with wiring diagrams?

The circuit is a little more than the parking brake switch and the IP light. Other circuits or components that could affect how the light works is the brake fluid level switch at the master cylinder (check level) and a signal from the electronic brake control module for fault detection.

The light at the IP always has 12v at one side therefore, to illuminate the lamp it takes a ground or low.

Do you have a GM service manual with wiring diagrams?

The circuit is a little more than the parking brake switch and the IP light. Other circuits or components that could affect how the light works is the brake fluid level switch at the master cylinder (check level) and a signal from the electronic brake control module for fault detection.

I don't have the factory service manual...

I am not getting a "Low Brake Fluid" warning light and the fluid level is approximately 1/8" below the MAX mark on the master cylinder reservoir...

I don't have the factory service manual...

It would be nice if someone had the applaicable wiring diagrams for that circuit on an Impala and provide that info for you. I have Regal and Grand Prix but there are differences in the wiring and the idiot lights on the IP so that won't help. The specific circuit would be where the parking brake switch output goes to the Electronic Brake Control Module and then up to the instrument panel warning light. The lamp driver circuit may be part of the EBCM module.

I've had a couple of people refer to the BCM possibly going flaky on me and causing this... Help me with the semantics...

BCM = Body Control Module ???
EBCM = Electronic Brake Control Module ???

These are different modules ???

I've had a couple of people refer to the BCM possibly going flaky on me and causing this... Help me with the semantics...

BCM = Body Control Module ???
EBCM = Electronic Brake Control Module ???

These are different modules ???

Yes, they are different modules.

I really don't believe your problem is the BCM but you never know. The BCM controls and monitors interior lighting, anti-theft (Passlock/Passkey), power door lock/unock, brake transmission shift (BTSI), retained accessory power (RAP), etc.

The ABS braking system and traction control system has a control module separate from the BCM called the EBCM. It is located somewheres under the driver's side of the dash. The BCM is located to the far left under the dashboard not too far from the emergency brake.

The only real way to tell is to review the service manual and wiring diagrams for your year and model Impala.