First, a cap for "looks" is just a silly statement. ALL caps are functional (unless you just bought the outer casing of one...lol) Everyone blames the ALT, well that is the biggest myth ever PERIOD. Why do your lights dim at idle because NO alternator makes big power at idle. You need to be at 2500-3000rpm before you see real power levels out of your ALT (amps). I had 6 amps in my SPL escort at max draw the total current draw was over 300A (this was measured and I blew a 200A fuse on a 20hz note with ease) That car had a stock ford alternator rated at 95A. We later added an adjustable voltage regulator. Even before that though, the lights never dimmed. Why because I had 4 extra batteries in the back to boot....LOL.
Too many people over estimate what truely is going on in thier car for the simple fact that they do not know any better. Before diagnosing anything make sure you use the proper tools.
So what have we learned? Your alt is perfectly fine if the lights dim. That is not how you "test" for a weak ALT. Now if you have a voltmeter, that would be the proper way of checking. Telling people they need an ALT because their headlights dim is just another "urban legend" that you are continuing to pass along for generations.....
95 Contour SE '01 3L 
