I put an alternator into my 7.3 the other day. no charging. I test the batterys and they are good. check B+ at the batterys, 12.35. Test at the back of the alternator, 12.35. talked to a friend and he told me to check the light green/red wire coming out of the alternator for B+ voltage. I get 0.0 on the meter. Does anyone know where the LG/RD wire connects in the 42 pin cannon plug and on the PCM connector? Thanks for the help.

 

It would be helpful to know the year of your truck.

Different years have slightly different wiring diagrams.

Pop

 

sorry, it is a 2003 E-450. I did some searching on here and found diagrams of the two bigger fuse/relay boxes. Neither looks to have anything labeled for the charging system

 

Started tracing the LG/RD wire. Found a small cannon plug connector right by the oil fill. Bad connector there. Butt connected and heat shrunk the wires together, and now we have charging!!

 

Thank-you for posting back on your fix

 

I hope it will help someone someday

 

That's what this forum is all about.

Reps sent!

Pop

 

Nice troubleshooting and thanks for posting your fix. Reps sent.

 

Does anyone have a wiring diagram of that charging system?

 

2003 F-450 charging system:
http://www.e-toolbox.com/ads/wiring/va169323.pdf

Pop

 

Thanks Pop,
Jus tryin to figure out how that circuit works and what voltages need to be where.
Nick