Hello all,

I'm new to this forum (as this is my first Ford too &#128513 and it's about time to pop my "posting cherry".


So, on to business:

My truck is a 2001 F250 with the 5.4 V8; upon engine starting, the charging system fault light stays on and the battery voltage steadily decreases.


The battery will run the truck for like 45+ minutes on it's own, so I'm not really concerned about having to replace that yet.


I checked fuses, ensured no corrosion at the connections and grounds that I could readily reach (there's not really much corrosion at all anywhere on this thing).. still no charging.


I checked battery voltage with my voltmeter and it was 12.35; then checked voltage between ground and the B+ post at the alternator itself.. 12.35. I assumed bad alternator and did the good ole R&R. Still no charging.


Removed the replacement and had it bench checked. Passed with flying colors. Good point to add here: it's not a reman part, I decided to go with a brand spanking new alt.


So that's basically where I'm at right now, just waiting for it to be tomorrow and less mosquito-y to continue.


I guess my next step is going to be checking the A, I, and S circuits. I don't have an ohmmeter anymore to check resistance, so I'm thinking of installing temporary jumpers one at a time to the I and A pins from the B+ to see if that kicks on the alternator. In an effort to narrow down my suspects. (I believe those two circuits receive 12v. "I" turns on the regulator and the dummy light and "A" is the battery voltage sensor. And "S" I don't remember exactly what it does but I /think/ it gets half of batt voltage and also is the one that makes sure the dummy light goes off once charging begins.. correct me if I'm wrong!)


I guess what id like to know is: Is there any advice or tips beyond that that anyone has to maybe give me a fresh outlook on this friggin headache?


TIA,

Dave.