Hi, new member here!
I recently inherited a 2000 ford explorer SOHC, Vin "E". I'm having issues with the charging system. When i got the truck about 2 months ago, it had a bad alternator ( parts store tested and confirmed). I didnt have the cash at the time, so i went to the junkyard and thought i got lucky by picking an exact match that looked darn near new, it was still shiny! ( I know that you cant tell if it works by how clean it is, but hear me out).
All was fine until the other day on my way home from work, the dash battery light popped on and the gauge started draining. connected the meter, and sure enough, the alt is not charging. Battery is confirmed to be good with no dead cells. I did a little online research and backprobed the voltage regulator plug. The yellow wire has 12v with key on, but the green/red stripe wire that should have one volt with key on, has no voltage with key on, or while running. Checked the appropriate fuses and they are good to go also. megafuse also has continuity between posts.
Where do i go next? What does the green/red stripe wire connect to? any help in troubleshooting is greatly appreciated, as electrical troubleshooting is admittedly my weak spot.
Thanks for any info/ help.

 

Welcome to the forum!

The light green/red tracer wire goes from the regulator to the ground side of the Charging System indicator in the instrument cluster. According to the factory service manual, the stator voltage to the regulator (white/black wire) should be approximately half the battery voltage when the engine is running to keep the charging system indicator off. With key on, you should expect the indicator to be illuminated which would be the case with anything less than 1 Vdc at the stator.

Have you confirmed if you have charging voltage to the Black/Orange (as well as the Yellow/White) wire at the alternator when the engine is running, or have you only been testing at the junction box or battery?

-Rod