electrical problems???? please help

[rockerguy]

hi everyone, i have a 1990 acura integra gs with an AT transmission. for the past few weeks ive been having some strange problems with my electrical system. the only mods i have besides exterior looks(body kit,carbon hood) is a push button ignition, hid headlights and glow guages. my problem is that all of my lights(headlights, guages,clock, radio,dome ect) are abnormally dim and my heater blower doesnt run as strong as usual. but when i hit a certain amount of rpm's(round 4000) everything gets super bright again and my blower runs noticiable harder but everything goes back to the way it was when the rpm's go back down. so basically seems like some kind of surge in the system. i try to not push my car to this point very often. whenever i go over 60mph i risk blowing my 70a fuse under the hood which im pretty sure goes to the alternator,has popped a few times by doing so. my battery and my alternator has been tested a couple diff times and they have checked out good everytime so far. ive also tried to inspect all the grounds i can locate and everything seems to be clean and in order. im assuming theres some kind of short under my dash. my stereo speakers went in and out one day and now doesnt produce sound but the radio still turns on. ive redone all the wiring to the stereo also with no luck. ive always thought that something was grounding out and have inspected everything i can think of but i cant seem to find the problem. any opinions or advice on what it might be would be highly appreciated. i also have a digital multimeter for testing.
thank you in advance

 

[BrokenTalon27]

Sounds like you're alternator is on its way to the grave. I understand that the test that was done read right, but I have a feeling if you change the alternator you'll find that it was your issue.
As for the lack of sound, the head unit may have been damaged somehow. I had a car at work this past weekend that had some crossed wires that fried the head unit. Could be something similar.