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2014 Chevrolet Sonic electrical gremlins

My 2014 Chevy Sonic has an electrical problem that the dealer cannot fix. The car will intermittently lose all electric power and just stop running. It is totally random and occurs at any speed. The dealer has tried to duplicate the problem but of course it never happens when they have it. They have run all diagnostic tests but nothing shows up. They thought they solved a few moths ago by replacing the battery cables but last week it lost power again.

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Keep all your records and receipts. Bump it up the chain to a regional headquarters, the phone number is in your owner’s manual.

Good advice Bill, thanks.

Is it on its original battery? It would not be unheard of to need a new one by now. The one you have may have an internal flaw. It may or may not be covered by the new car warranty.

New car?

The vehicle is 4-5 years old. And is probably over the 3 year/36,000 mile basic factory warranty.

Tester

The battery has been tested by the dealer and electrical output is fine.

Yes, but the problem is intermittent loss of all power. The battery may be intermittently not supplying any power. The rest of the time it’s OK. But that’s not reliable.

That is certainly something to look at, thanks

Ask your shop to install a volt meter in the passenger compartment where you can watch it as your drive. If it dips briefly below 11.5 volts while driving, even if that event doesn’t cause the symptom, that would be a big clue as to what the problem is. If it dips then stalls, even bigger clue. Be sure to record the pertinent conditions of the driving experience (lights on, AC on, turning, stopping etc) when you see those types of voltage dips as you drive. If the problem occurs but you see no voltage dip, then the shop can hook up the volt meter to a different circuit, and try again.

Even better if they do the above, then let one of their staff use the car as their daily driver, and meanwhile provide you a loaner. It may take weeks or months, but eventually I expect they’ll find it. Better for you if this is their problem, not yours.

There’s miles of wiring inside a car, and unless there’s something visually obvious, like a broken connector, its going to take some sleuthing to figure it out. But it can be figured out. Has the car ever been in an accident or flood?

Here is a little more information about the problem. After the power cuts out if I wait 5 or 10 minutes it will start again and I won’t have an issue with it for a few weeks. Very frustrating!

You can buy one from Amazon for $10 that plugs into your cig lighter socket.

https://www.amazon.com/DROK-Temperature-Multimeter-Motorcycle-Thermometer/dp/B015S6PVOU/ref=sr_1_9?ie=UTF8&qid=1523536521&sr=8-9&keywords=automotive+volt+meter

Great thanks!

Same thing happened to a friend of mine, same symptoms, intermittent. Ended up being something loose in the battery, when the car hit the right bump or whatever it disconnected for a few seconds, the car died. Then it would restart and not way to make the problem come and go. But a new battery fixed it.

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I think I’m getting a new battery!

It’s important that the battery is securely held down in its tray. If its hold-down apparatus applies force to the top of the battery, don’t put too much squeezing force on it.

The battery could certainly have an intermittent internal connection issue inside the battery case but if it did I would think the alternator would still keep things alive as long as the alternator field stayed up.

Intermittent problems like this are very frustrating to work on as they never seem to occur while you are trying to find the trouble. The trouble could be in a couple of other places besides the battery. The main power distribution from the battery ties to the main panel under the hood. It supplies to many things in the car and some things always have power going to them regardless if the ignition is ON or not. Like the horn, brake light circuit, and flashers. It would be nice to know if the horn works or those other things mentioned while the problem happens. If they do then the trouble could be with the power for the ignition circuit, or the ignition switch itself. Just like turning the key OFF. Another clue to the trouble is, do the warning lights work when the trouble happens? If they do then power to the engine systems need to be checked. These kind of clue help pin down the trouble area for the savvy technician to look into. If nothing works at all then you need to look at the wiring between the battery and the main panel under the hood, and the main fuse.

Everything shuts down no lights nothing at all. The dealer after many hours of searching strongly felt that the battery cables were the problem almost cost $700. Worked fine for a month or so then it happened again

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Well if nothing works at all, including the horn, then at this point it seems it would be wise to just replace the battery in case that is causing the problem, as it certainly could be. If that doesn’t help and the wiring between the battery and the main panel under the hood has been replaced then panel itself needs to be checked along with the main grounding between the battery and the chassis of the car and the engine. Tapping on suspected trouble spots with a screwdriver handle may show up the problem.

Since it doesn’t occur at the shop, I can see why they have a hard time fixing it. One idea, ask them to keep the car and one of their staff can use it as their daily driver. Eventually it will happen, and the staff will have some testing equipment on hand to trace it down on the spot. Loss of all power should be fairly easy to figure out if it is actually happening when a shop tech is there to probe the pertinent test points.

Here’s my related anecdote: Years ago my Corolla developed an intermittent electrical problem involving (as I recall) the main charging wire between the alternator and the battery. It was a big thick wire anyway. It would work sometimes, then stop working for no apparent reason at all. I had to completely unravel the main engine wiring harness (what a pain!) to finally figure it out. I discovered that battery acid was decanting a little bit at a time from the top of the battery down a wire leading into the harness, and then it slowly worked its way down to a point inside the guts of the harness where a wire spice occurred, which it promptly ate up. By the time I got to it, all but a few copper strands had been eaten away. It must have taken months or even years for the problem to develop.

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Actually they are doing just that. They have had it for 2 weeks.

Anyway I appreciate all of the suggestions from everyone, thanks!