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Intermittant dead electrical system

2007 Chevrolet Silverado 1500 Classic, 5.3L engine, 230k miles. A couple of nights ago, I got a call at midnight from my son who said the truck was completely dead, no lights, no noise, no response of any kind. I got up and was just about dressed when he called back to say the truck juut came back to life and started fine.

I was out today and it did it again. No electrical at all. The only non electrical thing I noticed was when I stepped on the brake before starting, the brake pedal was rock solid, like it had been welded in place. It is not a requirement to step on the brakes to start it but that is just a habit.

I opened the hood, pulled the relay/fuse panel cover and lightly tapped on all the relays and then shook the battery cables and then jumped in and it started right up. I got home and checked the Silverado/Sierra forum and found a few others had the same issue. Some immediately called a tow truck and spent lots of $$$ but the problem returned. Others shook the battery cables and drove home. The issue returned but each time, shaking the cables solved it for the time being.

I and one other noticed that the negative battery cable was loose. I pulled both battery cables to inspect them, no corrosion, mine has a new battery and then reinstalled the cables, making sure both were tight this time.

Just wondering if anyone else has experienced this and if the loose negative battery cable (not that loose BTW, but enough that it could be tightened with just a little torque. I guess it was about finger tight to begin with.

The infamous GM side mount battery cables.

Corrosion forms at the terminals of these cables and causes a poor electrical connection.

Sometimes this corrosion can’t be seen because it has leached down under the plastic cover where the terminals are crimped onto the wire.

Replace the battery cables.

Tester

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And check the rubber on the connector, after putting in a battery and no dice I cut off extra rubber on the cable face preventing a connection.

Somelthing similar happened to my Corolla one time. Electrical system went completely dead at a gas station, after I had just filled up the gas tank. Twisting the battery cables brought it back to life. Turned out to be just a loose connection at the battery post. I had to file the connector a little so it would clamp down strongly on the post as I wrenched the nut.

Another idea, I think some GM products have a history of problems with the crimp going bad at the ends of the battery cables. See Tester’s second photo above. You may need a re-crimping, or brand new cables.

Those side terminal batteries only take a 8mm wrench so many don’t get tightened enough. It is not uncommon to walk up to a “dead” GM car grab a cable and be able to twist it sideways with your wrist and have the car spring to life.

Yet another item that should be banned… side post batteries. Ugh… I usually cut away a circle of that rubber casing where the terminal meets the battery…It helps, but the side post should just go away.

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If the negative connection was only finger tight then I highly suspect you have solved the problem. Faulty battery connections and battery cables make up a pretty high amount of normal car problems. You also may want to apply some anti-corrosion sealer to the connection surfaces so corrosion can’t take place. If you still have problems with the power then check for power getting the main panel under the hood. The fuses in there should have power getting to them at all times, even when parked.

Here’s something that should be banned . . . because it does NOT work at all

And these are a joke . . .

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my side post Chevy van battery terminals are always coming loose. It is part of my monthly inspection now to check them for tightness.

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Not sure how hard it would be with today’s car’s but many year’s ago I bought my 2nd & last chevy truck it had the side terminal’s The 1st time I had a battery problem I in put a top post battery & both new cable’s in it. Just for the heck of it I striped the old cables to see how bad they were one the + it had corroded about a third of the way from the battery end on the - it was 2 to 3 inches. at the time I was living in a high humidity area not sure if that had anything to with it or not.

I wonder what’s the manufacturer’s motivation for using side posts? Does the application require a lower profile battery in these vehicles? None of my vehicles have ever used that type of battery, so never run into any side-post problems.

‘I have seen some of the older van’s mid 60’s to some where in the 70’s with the hood sloped enough to hit the post’ on a top post battery.

I have a feeling it had nothing to do with the space available

GM used it in seemingly most or all of the applications for several years, including cars and trucks that had plenty of clearance under the hood

In our fleet, we go through a lot of side terminal battery bolts. There’s only so many times you can clean them before they’re goners. And the threads do become rough and/or worn over the years.

It’s definitely not one of the better designs, in my opinion

It seems to have created more problems than it solved . . . ?!

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GM went to side-mount battery’s when the body designs didn’t allow enough clearance for a top mount battery where the battery sat.

This also allowed GM to reduce the cost for the battery terminals. Because if you install a small crimped on terminal instead of a large steel/lead clamp, that reduces cost.

So these battery’s became the standard for GM vehicles whether it had the hood clearance or not.

Hmmmm?

What other vehicle manufacturer has a side mount battery?

Tester

Now that you mention it I have never seen a side post on anything but G M there may be other;s my wife’s buick has them but the first time it cause’s a problem it will get a top post battery & new cable’s.