87 TII with 85K, car is mint and is my DD. A few days ago I came to a stop sign and when the car dropped to 750RPM the warning buzzer made a quick beep and the entire idiot cluster stayed lit. I turned the key on and off and sure enough the idiot cluster lights all stayed on.

The following day I started the car when it was cold and the warning buzzer would get louder as I revved the car, then when it reached operating temp and idled at the normal 750 RPM, it did a quick beep....again lighting up the full idiot cluster (and shift light)

If I beat on the car and and turn high RPM for a bit the lights will go out, as soon as it reaches idle it beeps and the lights come back on.

I did some reading and the alternator belt is still intact, and the battery reads 14.2 at idle. Any suggestions?

 

The warning lights come on while the car is running to tell you that there is a problem w/the alternator. The alternator will self excite itsel at high rpm's thus why the warning lights turn off. The White/Black wire at the rear sends a signal to the warning cluster. W/key to on there is a ground on the wire which causes the lights to turn on. While driving, and the alternator is working properly then the reading on the wire would be around 12 volts. If the alternator is problematic while in operation then the wire will read a ground signal.

 

at only 85k, I doubt it's the brushes inside the alt, but the regulator itself. It's still not really replaceable (or easily I should say).

Robert, do you have a multimeter?

If so, set it to DC volts and test the White/Black wire with the engine running (be mindful of the engine fan while doing this!).

 

That is for the help guys, ended up being the alternator. I forgot that I a spare alternator off my other car.bolted it on and it was good to go.