Brake warning light?

You have a rusted steel line or the wheel cylinder blew out. Neither of those are especially expensive or difficult to repair. The exception would be if the rear brake was worn out and grinding metal-on-metal and you ignored it. Be aware though that as a result of pressing the brake pedal further than normal, that can damage it on any vehicle more than about a year or two old, so don't be surprised if after the repairs are completed at the rear, your mechanic has to tell you a new master cylinder is also needed. There's no way for him to know that right away but many shops will warn you ahead of time to prevent surprises later. Even if your master cylinder is okay, some damage may not show up for a few days. When and if it does, it results in a slowly sinking brake pedal when you hold steady pressure on it, and the red warning light will turn on again.

The light will come on if either one of those problems happen.
If it's full, then you need to have it checked.
You could have a leak, a problem with the master cylinder, the proportioning valve.
Brakes are not something you want to gamble with.

It's one thing to throw your fan belt and be stranded on the side of the road, it's another to run a stop sign and crash into a bus load of nuns, taking kittens to an orphanage.

James:
Hi. Have you checked the basic things like the park brake switch, brake fluid level, level switch?

Have you checked the wiring to the sensor?

Based on what I could find, you must only have rear ABS. THe sensor is on the differential.

As far as the neutral safety switch, here is a picture of it. Let me know if it is what you are looking at. If it is, there should be power in from one wire, the other two should have power out only when in park or neutral. One is for starting, the other is for the back-up lights.

The switch you found in the differential is for the ABS. Make sure the wires are clean and making good contact. If they are, replace the switch.

As far as the neutral safety switch, it sounds bad too.

Two things. First, make sure the master cylender is full of brake fluid. If it is, check where the park brake is located to determine if the switch is out of adjustment or loose. The switch is located toward the top of the pedal.

Let me know what you find.

Joe

James, Let me know what you find.

Joe

I'm glad you found the problem. I have to be honest, that isn't a common problem. Regardless, if it is fixed, that is all that matters.

Let us know if you have questions in the future.

Joe