I'm having almost this same problem.
I've always had the problem of the headlights dimming when the car is idling and them brightening when the rpms rise. What is weird, though, is I was on the freeway and all audio went to 1 speaker, then back to all 6 speakers, then 5 minutes passed, and it did it again. Then my head unit cut out, and came back on. So, I'm thinking alternator or battery, alt. mainly as the battery is newer (1.5 years), and as I"m thinking this, the abs light flashes, then goes away. Later that night, I drive home, the same distance, cars starts up easily, and the whole time the ABS light is flashing, going away, continuously. The headlights, stay on, bright, but the gauge, and climate control knob lights dim and go out, and come back on, and the turn signals are still working fine.
I go to work 2 days later, car starts up easily again, and still have problem of ABS flashing, and when I lightly press brake pedal, I can feel the ABS activate. During my break, I bought a voltage meter, and checked both the battery and alternator when running. The battery was at 12.3-12.5v and the alternator pole was at 13.9-14v; idling.
I have driven the car no radio, and no lights as much as possible, with no problems starting the car up. Sometimes the ABS light will flash once I bring the windows down/up, or flashes when I hit the brake, and it flashes at times when the rpms are at about 3300-3500, with no added electrical load. But what is weird, is that just the particular gauge and climate control lights will go out, while the car is running and the head lights are unaffected.
I had no clue as to what is happening, until reading this post, and even now there are some complications when compared to the original post. Psycho5150, could you let me know which wire grounded out. I have yet to check the alternator wire for any exposure, but I'm certain it is still good as I reran the wiring around the engine compartment. Has anyone had this happen before???
