Thanks for the reply, NAJ. Yes, a code is set, a "16".
I know this topic has been beat to death, but I'm afraid I'm still missing something. My '87 2.2L Aries is charging at 18+ volts.
Here is what I know after the testing I've done so far:
--Supposedly good alternator, tested at Advance auto
--I have the required battery voltage from ignition switch feed for the F1 terminal on the alternator (lower terminal).
--I have the same voltage on the F2 terminal (upper) of the alternator when key is "on". In other words, continuity between F1 and F2.
--Resistance between the F1 and F2 terminals is 8-10 Ohms.
--The alternator ground is good.
--The Dark-Green and Orange Voltage Regulation Signal wire on 12-Way Connector between the Power Module and Logic Module has no shorts.
--I clipped the DG-O voltage signal wire mentioned above and stripped both ends. With the key "on," I had 1.88 Volts on the Power Module side of the clipped wire. I had no volts on the Logic Module side of the clipped wire. (I obviously fixed the wire after I did this.) This seemed strange to me because the car wasn't running. I would have figured there would be no volts at all.
--The two Light Blue and Red grounds on the Logic Module are good.
--The Logic Module battery voltage input (red and white wire) is battery voltage when key is "on".
--I ran new test wires from both of the field connections on the alternator to bypass the original wiring in case of shorts. There was no change--charging voltage still way too high.
All of this tells me either my Power Module or Logic Module is bad or both. The only other thing that bothers me is the continuity between the two Field connectors on the alternator. I keep having a hunch they're not supposed to read the same voltage or show any resistance at all.
Anyway, it anyone can shed any light on this, I would appreciate it. Tomorrow I'm going to pick up a used Logic Module from a junk yard close to me. I'll use it in continued testing I guess.
Thanks!
Dave