Our Saturn Vue randomly won’t start. It won’t turn over, no lights, and key can’t be removed from ignition. When this happens I get out, raise the hood, bang down on the top of battery case and Voila, lights come on and it will start. It might do it once a month or do or it might do it everyday for a week. It’s totally random. Multiple mechanics have looked at it and can find nothing wrong. Precursor to it sometimes is while driving, the car dings a sound and traction control light will come on. Anyone else heard of something like this happening?

 

remove and Clean your battery cable connections at the battery and make sure they are tight. Also check the negative end of the cable that connects to the body of the car. There may be corrosion that is causing an intermittent poor electrical connection.

With the battery connections off, check the battery to ensure that the connections for the cables are not loose within the battery. Sometimes battery acid will leak and start eating through the terminals on the battery itself. Had one fall off in my hand once.
I would advise you do not bang on the battery case. They are not designed to absorb a ton of shock. Now the force of you hitting it with your fist it's not as high as the force of a huge pothole, but repeated physical abuse will eventually take its toll.

Also, cut back about 2 in on the positive battery cable insulation from the battery connector end. If it is all crunchy, battery acid has been picked up into the cable and has chewed through a lot of it which ultimately will give you intermittent connections. the fact that you sometimes get a traction control light maybe coincidence or maybe an indication that the car's computer is not getting sufficient current at the proper voltage because there is a bad connection. Also check where the feed from the positive battery cable goes to the fuse box and where the other branch attaches at the starter. Pounding on the battery may be slightly adjusting the position of something else. You just never know

 

All of that has been checked multiple times. We have had it to two very highly recommended mechanics in our area as well as the GM dealership which kept it for three weeks. Their mechanic drove it to and from work for two weeks and it never happened when he had it. They’ve cleaned cables, replaced cables and they all assure us they can’t find anything causing the problem.

It happened about 6 weeks ago, took it to a different mechanic. He kept it 10 days. Replaced a cable. All has been good until this week and it’s happened 5 times in the last 3 days. It’s so incredibly frustrating!

 

Are you positive all that I mentioned, point for point, has been done?

Has anyone replaced the battery with a known good new battery?

Are there any indicator light lit on the dash?

You mentioned the key could not be removed. How do you get to this condition ?

Has the ignition switch been replaced?
When it has the issue,

Are you sure the screw connections at the battery are truly mated/not crossthreded?

Has anyone checked the voltage at the fuse box when this happens?

Has anyone checked the fuses and fuse slots for corrosion?

 

Great point! We only know what the mechanics are telling us so when they say they’ve checked everything we assume they have. The battery is only a year old and they tell us when they put it on the tester thing (can you tell I’m a woman, lol) that there’s nothing wrong with it. Maybe we should replace it anyway? I really appreciate your input.

 

This is the kind of gremlin you can pay 1000 to some people to not find, or call a friend over who is a good DIY guy w cars. Call him when it happens at home, don't touch a thing, and let him go at it. Can be a she. (No sexism intended).Many shops will do a cursory check, find nothing obvious, then stop looking on a 10 yr old vehicle with no parts support. Especially Saturns.

So it is likely something slightly non obvious.

I would start with the cable connections at the battery and a negative battery cable ground at the body of the car. And the positive connection at the battery and to the fuse box under the hood. Fell the big red cable.

The most simple explanation is an intermittent electrical connection. When you thump on the battery oh, you are knocking something back into place where it will conduct. Either that or there is an internal issue with the battery.

Resist the urge to throw parts at it. It gets expensive very quickly and except for things like a battery doesn't necessarily tell you where the problem was.

Also, the next time it happens, try to jump start the vehicle after gently attaching the jumper cables. This should give you a very good clue as to whether there is an internal issue with a battery.

Early in my driving life, I drove a 1980 Ford Grenada. Every once in a blue moon I would come out to the car to start it and I would get absolute silence. There was something not making good contact at the negative terminal. It seemed to be an internal issue to the battery because all I would need to do was lightly tap on the cable connection at the battery terminal and it would start right up. I had clean that terminal and cleaned the cable end many times it was tight enough. But that is what it took.