2000 7.3 electrical problems

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Jan 24, 2013 | 06:33 PM

watatrp

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Joined: Jul 2011

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From: South Bend, IN

2000 7.3 electrical problems

Trying to diagnose a problem w/ my daughter's Excursion. 2000 w/ 7.3. Died the other day while running. Found out that one battery is completely discharged. The other is fine. Batteries are less than six months old. Took the battery in and it can be charged and holds a charge. Put it back in and after driving for a few miles, the battery is losing it's charge again. Alternator is putting out almost 13v. My guess is the wiring to the bad battery is bad. Both batteries should be connected to each other right? Seems like the battery that is losing it's charge is not connected to the alternator. When it dies, takes a jump to restart. Any ideas?

Jan 24, 2013 | 06:38 PM

BigAlsPSD

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From: Pea Ridge, AR

The batteries are hooked to each other in parallel, positive to positive, negative to negative(although the neg is not directly wired to each other in this case), and the alternator from the factory has just the one positive wire attached to the DS battery.

Jan 24, 2013 | 07:13 PM

BWST

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From: Lake Stevens, WA

13V seems a little low for the alt output. Should be just over 14 I think. Worth checking the connections though first like you're doing.

Jan 24, 2013 | 07:20 PM

srteach

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Joined: Mar 2012

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https://www.ford-trucks.com/forums/1...tor-issue.html
Take a look at that information. Read all the posts, since I won't retype it. Thread from earlier today, same situation.

The alt should be putting 14-16V out when running. 13V is too low to run the truck and charge the batteries.

Jan 24, 2013 | 07:38 PM

watatrp

Thread Starter

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Joined: Jul 2011

Posts: 66

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From: South Bend, IN

Quote:

Originally Posted by srteach

https://www.ford-trucks.com/forums/1...tor-issue.html
Take a look at that information. Read all the posts, since I won't retype it. Thread from earlier today, same situation.

That is too funny. That's my son-in-law. Guess he's taken it on himself to learn about his own diesel. Sounds like he's headed in the right direction. Might be in my garage this weekend replacing an alternator. Spent enough time yesterday running his family around. He owes me dinner.

Jan 24, 2013 | 07:44 PM

srteach

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You might be replacing an alt this weekend, too.

WAIT A MINIT!!! I've been help you and him on the same truck for the same problem?!?!? Damn!

Jan 24, 2013 | 09:46 PM

howellt39

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Joined: May 2011

Posts: 454

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From: Portland, OR

Quote:

Originally Posted by srteach

You might be replacing an alt this weekend, too.

WAIT A MINIT!!! I've been help you and him on the same truck for the same problem?!?!? Damn!

If that ain't good for double reps I don't know what is.

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Jan 25, 2013 | 11:51 AM

crop harvester

Fleet Mechanic

Joined: Jul 2011

Posts: 1,667

Likes: 5

if that bad battery is internally shorted,you might not be able to diagnose the alternator until batteries are taken care of first.hopefully the batteries haven't already killed the alt.