Electrically (almost) dead Sonata 2009

Daughter-in-law pulled into parking place and shut off engine. Then realized she had to adjust the car’s position, but car would not even turn over. Her husband had recently cleaned corrosion from battery terminals; battery is about 4 years old. I took a quick look:

Battery measures 12.73 volts on DMM.

No lights, horn, dashboard, radio, starter, nothing EXCEPT…

“Door open” light on dash and marker light on inside door panel come on.

12VDC is getting to the fuse panel adjacent to the battery, and I can find 12VDC on some of the fuses.

All the visible fuses look OK.

All we have available is the Owner’s Manual, which has mysterious designations for Fuses and Fusible Links.

I’d think it’s something simple, but don’t feel like guessing my way around. Any quick suggestions before they have it towed?

Everything-off (unloaded) battery voltage looks ok. Doesn’t mean battery isn’t the reason for the fails to crank, but faulty battery seems unlikely. In order for engine to crank the transmission (or clutch if manual) safety switch has to work. I’m guessing that’s your problem. Try cranking in N rather than P (if automatic). If still no crank, try jiggling the transmission selector with key in “start”.

Still a no-crank? Ask shop to measure the voltage on the “s” terminal of the starter with key in “start”. It should be at least 10.5 volts.

Door open and side marker warning lights could be related, but my guess, those are different problems. they aren’t problems at all of course if a door was open and/or a side-marker bulb isn’t working.

12.73 v from the battery says it is likely OK.

Check the starter relay in the fuse box
Swap it with an identical one nearby. If it starts the relay is bad. If it doesn’t it may be a bad starter. What is the voltage at the starter?


I’d double check the connections to make sure they are clean and tight…
The few things that are working don’t require a very good connection.


Yes always go back and check recent work. O cams razor. Suspect connections to battery.

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Your son in law should perhaps have left well enough alone.

The tow truck was arriving while I was back home sending the original post. The tow operator got the car running with a jump start. My son elected to get the car into the shop to make sure there was nothing wrong other than battery. New battery seems to have fixed everything.

I guess some sudden failure causing high internal resistance (which is not really an answer). Symptoms are still puzzling – why did one low-load light come on, but nothing else??? I’m not going to analyze it any more, unless I’m having trouble falling asleep.

In original post I neglected to mention that I had moved the shift from P to N (you guys have taught me about the N-P safety switch). I had also checked that the battery connections were tight and looked clean; I measured voltage at the cable terminal bodies, not on the battery posts.

I did not consider checking the voltage at the starter because I did not want to crawl under the car. And I don’t know how high I would have had to lift it to access the starter terminals. And it was cold. And I had only a little time. And I’m too old for that kind of stuff :>)

I considered swapping relays, but I wasn’t sure which one to check and which ones were identical.

Thanks for all the advice, except the comment questioning my son’s competence. He’s handy enough and smart and wise enough to know what he should not be doing.

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We have all goofed enough to point out things to check. Years ago it was about -20 out and the battery was dead at the store. I went and got a new battery and put it in. When I got the car home I discover I had failed to plug the alternator back in again after working on it. Just sayin is all don’t take anything personally.

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A failed battery can measure voltage as being fully charged but have no available amperage.
The next step would be to measure the battery voltage with the ignition in the run position and in the crank position, under load.

Years ago, power passed through the neutral safety switch for the starter solenoid and reverse lights. Today a transmission “range sensor” is monitored by the computer for gear position, no longer a load-bearing switch and failures are rare.


I pulled into a gas station at night , cold in pouring rain one time, (Corolla). Car was running fine. When I tried to start engine to leave gas station, turned key to “start”, the only thing that happened is all the dash lights went dim … lol … wouldn’t crank at all. I lifted hood and discovered I could turn the battery connector very easily on the post. I turned it a couple times, then it cranked ok. Later , back at home base, I properly cleaned & tightened the connections at the battery posts, never had that problem again.

I wasn’t anticipating you’d crawl under the car mid-winter to measure the starter s-terminal voltage btw. That’s why I suggested you ask a shop to do it. Warm inside shop and they have a lift. I’ve suggested this idea many times here and nobody has every come back and reported what voltage the shop measures. They just never come back. I presume when the shop makes that measurement it becomes obvious what the problem is. So just b/c they don’t come back reporting success after making that measurement doesn’t mean they didn’t achieve success.

Thanks, again for the advice and education.

George_San_Jose1 (and others) – I’d like to know what the shop did, but I’m out of the loop. The shop has a good reputation in the community.