Truck Died Last Night on a Main Thoroughfare, replacing batteries in 2 hrs or so, what may be needed? (Details in thread)

[Lost1wing]

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What do you mean by blown? What’s best method to use voltmeter to check? Red to post, black to main ground?

Typically red goes on positive and black goes on negative. Most digital type meters will just represent the results with a neg sign if connected backward. Older analog meters you will notice the meter trying to move backward.

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[ShadowsPapa]

I'm not seeing a good outcome if he is only seeing 11.8vdc. I'd like to see the results of the voltage test of n1 n2 n3 and n7 . Maybe he forgot to plug in the ibs? I wonder what the alternator will put out if still disconnected?

Exactly. That's like running a vehicle off the batteries with no charging system output.

 

[Lost1wing]

To actually check a fuse (there are several in that array) you need to disconnect it.
If you simply use a volt meter, it's going to show voltage in any case.

Yes sort of. If n7 is blown he would see 14ish volts with the engine running and battery voltage on the others. If n3 is blown, term n2 will read 14ish volts with the engine running and term n1 and n3 will be battery voltage.

If he does not see any differences, pulling the fuse array can be done at that point. I'm hoping something didn't get connected.

 

[tjk]

Main battery currently reading 13.11 V when main connections are disconnecting. Will try to get the posts next.

 

[ShadowsPapa]

Yes sort of. If n7 is blown he would see 14ish volts with the engine running and battery voltage on the others. If n3 is blown, term n2 will read 14ish volts with the engine running and term n1 and n3 will be battery voltage.

If he does not see any differences, pulling the fuse array can be done at that point. I'm hoping something didn't get connected.

Yeah, that's better detail.

 

[Lost1wing]

Main battery currently reading 13.11 V when main connections are disconnecting. Will try to get the posts next.

13.1vdc is good with the engine off. I'm curious what it reads with the engine running.

 

[tjk]

13.1vdc is good with the engine off. I'm curious what it reads with the engine running.

Standby, will try that. Just disconnected N1 to try to test, car shows no power.

 

[tjk]

14.3V with engine running

 

[Lost1wing]

Now, if you only see battery voltage on term N3, your N3 150 amp fuse is blown. If you see 14.3 volts there and the main, you should not see 11.1v on your display.

 

[tjk]

Now, if you only see battery voltage on term N3, your N3 150 amp fuse is blown. If you see 14.3 volts there and the main, you should not see 11.1v on your display.

do I test this by disconnecting all others posts except N3? Because when I tried to do that with N1, the interior showed no signs of power.

 

[Lost1wing]

Standby, will try that. Just disconnected N1 to try to test, car shows no power.

N1 is coming from your Aux battery. You will have no power if disconnected.

 

[Lost1wing]

Leave everything connected. Start the engine, black test lead held on the main neg post. Red lead on main positive write it down, move red lead to n1 term, write it down. Move red lead to n2, n3 n7, writing each down. It takes 10 seconds.

 

[tjk]

Leave everything connected. Start the engine, black test lead held on the main neg post. Red lead on main positive write it down, move red lead to n1 term, write it down. Move red lead to n2, n3 n7, writing each down. It takes 10 seconds.

Thank you, I will do that shortly and report back

 

[Lost1wing]

Your N7 fuse is good from what you have already said. With the engine running, your N2 term and main battery should be reading the 14.3v. Now if you N3 fuse is blown , N1 and N3 should read battery voltage (aux battery). If you read 14.3 on term N3 and only Battry voltage on N1 N3 fuse is good but your power control relay is open.

 

[tjk]

Leave everything connected. Start the engine, black test lead held on the main neg post. Red lead on main positive write it down, move red lead to n1 term, write it down. Move red lead to n2, n3 n7, writing each down. It takes 10 seconds.

Main: 14.3V
N2: 13.6V
N3: 9.89V
N7: 0 V

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