87 supra dash lights

[supranerd1987]

hey i have a 87 n/a supra, its seems like when i rev it to like 4000rpm the brake, rear tail light, and the battery lights all come on the dash. sometimes it flashes then goes away. then sometimes stays on until i rev it high then goes away. or sometimes it doesnt come on at all. do you think it could be a factory code for something or am i in for an electrical diesaster? please help!

[Jeeves]

Sounds like your alternator is failing. It's common for many lights to appear when an alternator is going out. Never heard it happen at a specific RPM though.

[CraigW]

Alternator problem, Could be just the brushes are worn out. Check out the truck section and there was another thread with DIY on alternator dissasembly.

[supranerd1987]

hey thanks, i had a feeling that the alternator was going out because if i have alot of accesories on ( rear defroster, headlights, wipers, radio, fan....etc) the voltage drops to 12v then when i rev it up it goes back to 14v. hey thanks again oya how long do you think i have until it fails complely any idea?

[Jeeves]

There's not a good way to predict this. Replace it before it can damage other electrical components with brown outs.

[mike787]

supranerd1987:

"hey thanks, i had a feeling that the alternator was going out because if i have alot of accesories on ( rear defroster, headlights, wipers, radio, fan....etc) the voltage drops to 12v then when i rev it up it goes back to 14v. hey thanks again oya how long do you think i have until it fails complely any idea?"

You can check the alternator ouput with a voltmeter, put one lead on the positive nut of alternator screw, and the other to ground. With the engine running the output should be 14 volts for the battery to be charging. If less, your battery may not be charging or will discharge completely soon and you should replace your alternator.