hi fellow bricksters-

I wrote about this problem a month ago (june 27), when it was an intermittant problem - now it's happening every time i start the car - the charge indicator lights up dimly. (got new battery and alternator in december that was installed by mechanic, things were fine until late may). i'm a total beginner mechanic (so please bear with my "silly" questions for things that may seem glaringly obvious), but i tried a few of the things that were suggested in the replies to my earlier post (thanks bob c, tom d, chris and nkfro!):

1) checked and cleaned all battery ground connections, including the ground strap from the valve cover - this strap is pretty grungy looking, so i will probably replace it.

2) a little corrosion on the positive battery cable wires (the part that's not covered by plastic insulation) - how much would you consider to be a problem? the plastic isn't crumbling, but the wires are a bit dirty and green on the outside.

3) wiring harness actually looks ok, as far as there is no crumbling insulation that i can see. i STILL can't really see the black ground coming from the alternator - there is a black wire that has a clear plastic cover on it at the connection, but i can't get a good peek at where it goes. the grey box just outside the firewall is filthy tho - would you suggest pulling all the wires and cleaning it out? or is this not so critical?

4) turned key to position II, and had assistant (a.k.a. my dad) unhook the thin red wire from the alternator - all the indicator lights on dash went out EXCEPT the check oil light - is this a clue to something??? if so, what?

5) voltmeter readings a week ago were 12.55v across batt terminals with car off, and after starting and running the car several times in the past week, they are now down to 12.4v with car off. i tried to take a reading with the car idling in neutral from between the alternator a) thin and b) thick red wires and a car frame screw head as a ground, but got a very strange reading of 0.14v . i don't think i was reading things right - i mean, it's a new bosch rebuilt alternator that's barely 6 months old, so it should kick out a bit more juice than that i would think. any very specific tips on how to properly read alternator output? does the alternator casing itself act as a ground? which part of the engine block would make a proper ground?

6) anybody live in chicago that has experience working with 240s? i'd be very grateful for "hands-on" mechanics tutoring, as i'm feeling way over my head with this car (previous owners didn't take care of it too well).

THANKS FOR ANY HELP/SUGGESTIONS!!!
-kathryn