Hello everyone,

Newbie here, and not much of a mechanic.

Wondering if someone can help me out.

My truck usually runs fine, voltage on gauge while driving reads a little to the right of half-way.

The other day, the CEL came on, voltage steadily declined. I headed straight home.

Code 41 - Generator field not switching properly or
Alternator field control circuit open or shorted

Battery checks fine, alternator checked fine at parts store.

I cleaned all the connections and cleared the error code.

Before starting I have 12.67v at battery. At idle, I have 14.2-14.3v at battery. When I turn on headlights, fan blower to high, wipers on (that's all I have), and hold 1500 RPM, battery voltage stays at 14.2-14.3v.

CEL has not come back on.

So here's my question:
Is it normal that battery voltage stays at 14.2-3 no matter what? No matter what I turn on, no matter what the RPM?

Is it possible that as I drive around with no accessories on, the constant 14.2 will overcharge the battery and then cause alternator to shut off, which is what seems to have happened, as described above? In other words, have I solved my problem or is it just going to repeat after I've driven around for an hour, and might be quite a ways from home?

I can just drive around and stay close to home, but would really like to know if alternator/voltage regulator behavior is normal as far as the tests I conducted just now are concerned.

Any practical or theoretical help is appreciated.

 

It's a good thing to have 14.2V all the time. That will not overcharge your battery. I wonder if you had a bad connection and you fixed it when you removed and replaced the alternator (which I'm assuming you did to have it checked at the parts store).

 

Thanks for the reply, Tom. Yes, I took some fine grit sandpaper to all the connections before re-installing the alternator.

So far, so good but will definitely not stray too far from home until I'm pretty sure the charging problem is solved.