how do you test SBEC Computer

[blathan]

ok so i just replaced my alternator and vehicle is running a lot better, however it is still over charging. I have tested all wires, circuits, fuses, fusable links, etc. have not tested computer. somone told me on another thread that the SBEC controls regulation of the charging system. how can i test this computer to see if it is the cause of the problem. if it is how can i get one inexpensive or is there an inexpensive alternative to replacing it.

[langer1]

The regulator is in the ALT I think in 93 or the ECU, I think the SBEC monitors voltage but don't control it.

[Matthew Currie]

I presume that in this case, the term "SBEC" is referring to a single board engine computer. The number of terms for these gadgets is pretty confusing, especially when it's not even consistent in the manufacturer's books! But just for information, and because it's likely this is how you'll usually see it on this forum, For the Chrysler era (91-up) systems the factory terminology for the thing is the "PCU." The Renix era term for the same thing in 87-90 vehicles was the "ECU." Anyway, in a 93, the voltage regulator is a part of the PCU. There is no regulator in the alternator.

So now what we need to figure out is, first of all, how are you measuring that it is overcharging? Don't rely on the in-dash voltmeter. Also, have you checked the battery? It's unlikely unless your battery is really bad, but sometimes it will overcharge, or seem to, if the battery doesn't take a charge properly.

[5-90]

It might also be instructive to measure field voltage at the back of the alternator - to see if anything is actually getting there in the first place...

It shouldn't be anywhere near battery voltage - but it shouldn't be zero, either.

5-90