My buddy has a '92 but won't be in contact with him until Monday, I will check his. I believe there should be a regulator somewhere though, on or off the alt. Troubleshooting questions:
1. running extra lights? If so, did you create a circuit or did you splice in somwhere?
2. Have you been having any trouble with your blower motor, stereo, startup, power door locks?
3. I ask #2 because the ECU and alternator both control a lot of things, best thing you can do is go through a wiring diagram from the fuse box-run to the alternator and ECU and see what primary circuits run through whatever other problem you've been having. If you haven't, Could very well be the regulator for alt. If not their, really have to dig.
I am not saying this isn't the ECU, but it's worth it to check other items before you spend all that money not knowing if it will fix your problem.