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Discussion Starter · #1 ·
Have a 2002 Silverado 2500 HD with the Duramax. The truck wouldn't start one day, had no power at all. Batteries are under 2 years old. I noticed some corrosion on the at the terminal end of the battery cables so I cleaned them up. Still no power at all. So I went home to get my meter and came back. I disconnected the batteries from the cables and tested with the meeter - both are good, around 12 volts. I re-connected and found that I have power. Tried to start and the starter just clicks. Looking at the forum, I have several things to check out.

However, I have one question concerning power from the batteries. My dad thinks that only one battery would be live all the time and the second one would be engaged when trying to start. Is this true?

The reason I ask is, when I had the batteries disconnected to test them, the drivers side battery sparked when I was connecting the negative cable (did positive first). When connecting the passenger's side battery, I connected the positive, then kept hitting the terminal with the negative and couldn't get it to spark at all. I figured it should if there is a circuit.

thanks in advance for any responses,


· Premium Member
18,259 Posts
The batteries are wired together -- so they make ONE BIG battery. When you disconnect the batteries and then reconnect, the spart is the computers loading up again. IF you have a good battery and a weak battery, the weak one will drain the good battery down.

I suggest you have the batteries tested, because 12 volts is probably not be enough to start a diesel.

8,062 Posts

To the op: Change your batteries,they are probably shot!I consider myself very lucky because our 07 dmax has original batteries,however I have to replace the batteries on my 06dmax every two years.....I'd bet the batteries are too weak to do the job,they are probably dropping in amperage as WELL as voltage upon trying to crank the truck.IIRC just the glow plugs take an initial 110 amp burst from the batteries on cold days..
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