lights dim when braking

[qvester]

I have tried redoing every ground i put grounds on both sides of the motor and i grounded the altenator and it still does it whenever i brake my rpms drop real low and my volatge meter on safc goes down to like 11volts i have been having this problem for awhile and i can't figure it out. in the morning when i start my car i have to rev to 2 1/2 rpms before the voltage will go up past 12v i have had altenator checked and battery checked any info will be helpful 1989 240/w sr20det.

[radhaz]

Possible ground in your brake circuit?

Are you getting 14v across the battery when the engine is running?

I've seen the kragen bench test fail at detecting a faulty alternator.

Just food for though, good luck with the troubleshooting.

[Pacman]

I would say that your voltage is not making enough volts to take the extra brake lights. Replace your alternator and you may find it to stop.

[qvester]

ya taht is what i was thinking it has to be the altenator i guess i will try to find an sr one on the net see go from there thanx

[CHOUKI240]

Check corrosion on all grounds and connectors. get a multimeter and test the bulb connectors and the wiring. Alternator might solve it but it could be a resistance in the circuit.

[ledzeppelin240]

Check the voltage and resistance of the grounds, the voltage should be near zero same with resistance.

[Phlip]

Engine braking, downshift