Brake idiot light on and off

On my 1997 Taco the brake idiot light comes on for a few seconds then off at semi random times. Usually when taking off first thing in AM but randomly throughout the drive. Been doing it for years. I thought it was the park brake that was loose. It used to be that it quit if I pushed the park brake handle in firmly. I tightened the cable by the book and now the on/off shows up. It may have been there all along too. Is there a sensor for vacuum assist? Could I have a vacuum leak to the tank? I'm hoping this is not related to ABS.
I also have a sharp vibration when braking hard. That may be the rotors. I had them turned at last pad change and they may be too thin and warping. Don't know what the ABS feels like.

 

check and see if your brake fluid is low, that will cause this.

 

I did think of that and it looks good.

 

I believe your brake light problem is not a serious one. Your parking brake has a warning sensor that tells you it is on or of by the light. Yours may be broken and you can find out by looking at the parking brake handle that is under the dash and find the wire that goes to the parking brake sensor. You can disconnect the wire and drive it to see if the light stays off. If the light stays off, then you need to change out the bad sensor on the parking brake. If the light is still on after removing the parking brake wire, then you may have bad or gummed up sensor on your brake master cylinder. This could be more serious, or not, the sensor may be able to be removed and you could clean up the probe end of the sensor and see if that lets the light go out. If that doesn't help, then the light cold be warning of a master cylinder problem. Good Luck.

 

Thanks folks. Glad to know the only sensors for that light are on the p-brake or mast. cyl. I messed w/ the p-brake sensor when I adjusted it but did not pull the lead.
I will now mess w/ it and maybe flush and fill the mast cyl. The system could use a flush anyway. She's showing her age!

 

Well it's fixed! I feel sorta dumb. I looked in the owners manual (what a concept) to find all the info for the meaning of the light. The fluid was between min and max. I filled it to max and the light stays off. I guess that being between the two limits is why it came on and went off - right on the cusp. Next time I'll look at the book sooner.
I did unplug the sensor wire and plugged back in just in case it was a connection prob. I'm sure it was the level. Now to flush the system when I have time.