240 electrical problems?

[slazzer]

I just bought a 91 240sx LE and had a problem with it, and I cant find the solution. When we first test drove the car, it wouldnt start so we boosted it, and it ran reletivly fine. I have had to boost it a couple times after that so I figured I had a poor battery, but i continued to drive it. I thought it was finally running fine, when it quit on me when i was driving. (No electrical, all lights went dead). When I got AMA to come boost it, it wouldnt hold a charge, so right away i assumed that it was the battery seeing as how I had problems with it before. So i then replaced the battery, and everything seemed ok, until a few days later when i was letting it warm up and the interior/exterior lights would dim slightly, and the heater would not be at full power. When i would rev the engine the lights would come back to full brightness and the heater would come back to life. So it seems as though i havent fixed the problem. I havent had any problems starting it since the new battery, and I am pretty sure the new battery helped but it appears as though somthing is still wrong. Any Ideas? I am very confident it is not the alternator either. When the engine is revved eveything works smooth. One idea that i was told is that it could be the voltage regulator. Any help would be great.

[NISTECH]

the voltage regulator is inside the altenator. so basically you need a new alt. most auto parts stores will bench test it for you if you take it out and take it to them.