I hate electrical problems
Posting Guru
Joined: Apr 2015
Posts: 1,817
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From: Yakistan, WA
If one battery is bad, or has less voltage than the other, it will bring both of the batteries down (or the other battery)
This is why we change new batteries in pairs, and ensure that both batteries read the same before we purchase or install.
Take it to a mechanic. They can hook up a computer to it, and watch where the draw is coming from, after the truck has went in "sleep" mode. Takes out the head ache, and your usually only out about 1 hour shop time.
I did this with my truck, took it to my mechanic. Although the "draw" I thought I had, was all in my head.... But then again I have mental problems.......
This is why we change new batteries in pairs, and ensure that both batteries read the same before we purchase or install.
Take it to a mechanic. They can hook up a computer to it, and watch where the draw is coming from, after the truck has went in "sleep" mode. Takes out the head ache, and your usually only out about 1 hour shop time.
I did this with my truck, took it to my mechanic. Although the "draw" I thought I had, was all in my head.... But then again I have mental problems.......
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Mountain Pass
Joined: Apr 2008
Posts: 228
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Nvr mind, it was dealing with something else. But to rehash the issue, the regulator I was sent was black which I am fairly certain is a F785hd. I ordered the F794hd though. Is there a significant enough difference?
Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
Load test the batteries. Replace as a set. Sounds like sulfated batteries. How old are they? Buy the best battery you can afford with at least the minimum required CCAa. I like to go a little higher on CCAs over the factory recommendation.
Fleet Owner
Joined: Apr 2008
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From: 0,0,1
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Fleet Owner
Joined: Apr 2008
Posts: 24,323
Likes: 5,133
From: 0,0,1
Right it's a push-pull effect and it makes each battery try and compensate for the other.
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Mountain Pass
Joined: Apr 2008
Posts: 228
Likes: 0
And so the saga continues, cranked the truck up last night to try and get it home, battery voltage goes to 15.93, battery light comes on and she throws a code. Code is for glow plug #4. Think the code was p0674 or something similar. Either way, dcp alternator ordered from Ed today and I'll chase wires to make sure I don't have chaffing and then may look at replacing the glow plugs as I believe they're the original