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Alternator 2003 F350 7.3 diesel crew cab

1K views 2 replies 2 participants last post by  Glide2277 
#1 ·
I own a 2003 F350 Dually 4x4 Crew Cab with a 7.3L diesel engine with 2 batteries and a single alternator. Does anyone have a wiring diagram for the alternator/charging system?
The alternator has one large Black/orange copper wire that dissapears into a a few wire concentrations, but seems to reappear at the right side battery positive.
The alternator also has a wire harness with positions for 3 wires but only the first and third are there...one is orange and black, the other appears to be yellow or yellow/black
I have two brand new batteries, and after a 5 hour drive they drained completely.
I do not believe the battery charge light ever came on, or at least not until the truck stopped running.
i have a bunch of questions would be great to get the answers.
1) does anyone know what the yellow/black wire does
2) what does the other small wire Orange/black do?
3) does my alternator communicate with the ECM---I think it would need two wires to do this so it seems like there is no computer control on it
3a) i guess that means it relies on an internal voltage regulator that senses voltage and turns the alternator on and off
4) How does my alternator know when to kick in and start letting out power to charge the batteries. (and by what wires)?---messages to voltage regulator?
5) how does my alternator know when to kick in and start letting out power to run the onboard electronics. (and by what wires)? (how is the voltage regulator notified)?
6) How does the alternator know when to stop charging so as not to over-charge the battery--and by what wires?--how do the batteries signal the voltage regulator?
7) is there a fuse that controls the alternator or effects it (if so which one?)
8) is there a way--i would really like to know this--to bypass the voltage regulator and just set the alternator to delivering electricity..full field voltage regulator bypass...I know this is not good long term but could. help me not get stuck in desert i think...
9) is the voltage regulator on my alternator built in--it seems like it is....

well, i. have a lot of other alternator questions but ten seems to be a good number to start with...


I plan (once my batteries are charged) to
1) clean, re-check and tighten all connections
2) Check fusible links (not really sure how to do that)
3) Check to see if the alternator is ever coming on
4) Check to see if there big orange and black line completes a circuit to the battery positive.
5) Check to see if the alternator is properly grounded to the negative pole of the battery via the engine bolts
6) check resistance (i really don't know how to do that, but it seems straighforward)

any answers or suggestions are appreciated and welcome!!
thank you!
apologies if i have done this completely incorrectly!
thanks
max
 
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