At night when lights, radio, fog lights are on, and I hit on the brakes the lights dimm just a bit. Like is loosing DC power, or needs more amparage to hold everything. I recently replaced the brushes on the alternator, thinking that would do it. Is it the battery, about to go? I had this issue for years, and I still have the same battery.

What controls the DC to everything in the vehicle.
thanx

When the ignition switch is placed in the RUN position, voltage is supplied to generator terminal L by the PCM, turning on the regulator. The generator'* voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator F terminal is connected internally to the voltage regulator and externally to the PCM. The PCM monitors the field voltage on the generator F terminal.

I have the same issue in my 97, just thought it was something that was normal and I had to deal with. When hitting the brakes the lights dim for a sec.

So, how do I fixed the problem...? What needs to be replaced so it outputs 100% voltage?

First thing you do is pull your battery cables, remove the rubber boots and check for corrosion at all ends of all cables. Clean all the connections and reassemble. Then test.

Most of the electrical issues we see here are remedied with this simple process that takes about an hour. The B'villes are very picky about power and always show us the problems.

got it i'll get on it