Hey all!
So while driving today on the highway all of a sudden every warning light on the dash came on and trip meter and mpg reset. I was going about 75mph, cruise and eco mode were on. I was listening to the radio. Nothing cut out, no engine sputter, just like a dash reset.
This kinda worried me as about two or three weeks ago I went to start my car and the battery was dead. Not dead just barely not enough juice to start. I had to jump start it. Then worked just fine. Till now.
Anyways after the dash situation I took it to AutoZone and had someone test it. They said the alternator failed. But I have to mention they literally had to ask me which one was the positive and negative battery cable. So we started the engine and it didn't read any increase in voltage so it said failed. Engine was pretty warm so when it started it just want to 500-700 like normal. So again kinda nervous, priced the alt and oh damn.
So went from there to Walmart. Figured if it dont start, id call the roadside assistance. It started just fine. I shut it off then checked the battery and it said 12 (my old fluke multimeter doesnt have a decimal). So i started it and at idle it read 13. Hmmm seems weak. But ok try and drive home.
Drove home this time with lights on, blower on 2 and sat radio on. Car ran just fine. I dont get it.
so when I got home I decided Id test again. This time Ill rev the engine some and hold it at 1500rpm. Because I had to get my rpm over 1000 on another car i had.
So holding it between 1.5k and 2k rpm the multimeter read 14. Tried ir with lights on, ac on, radio on, door open, you name it. The voltage didn't change at all while flicking all that on and off.
I also want to add the drive home is a 25 mile trip. Last time I had an alternator go out I barely made it that far.
Im so confused. Im thinking why would the dash reset it self but car work fine? Is this related to the dead battery type issue? I have no clue.
Anybody anywhere have any clue of what else i can check? Or what might be going on?


2017 Hyundai Accent SE Hatchback
61XXX miles

 

Something to think about,
There could be a problem with the battery or cable connections. If the connections to the battery from the alt are corroded or with some resistance it could tell the charging system "No more fully charged" and really not be fully charged.
A thorough check by a competent shop should provide more accurate results.
Batteries usually last more than 3 years, so that is kinda iffy. Don't know what kind of maintenance you vehicle has received, but that can tell us a lot.
If there are poor ground connections , that can also get into the picture.

 

Would clean up battery posts and cable terminal ends
Follow negative cable to chassis and clean up grounding point.
Do same for engine ground strap
This should clear up issue if it is the connections or corrosion

If not then deal with it as it comes up

 

Only thing ive had done was an oil change in January at the dealership where I bought it. And they do a multipoint inspection. Only thing they said was next oil change might wanna change the air filter. I drove it this morning with no problems. Im gonna schedule an oil change this week and have them run the codes and see if that logged anything. I checked the terminal ends and the grounding cable. Didn't look corroded and was tight. Awesome that the warranty just expired cuz Im technically 2nd owner since the dealer I bought it from bought it off another dealer (Was hyundai dealers loaner car) and now its messing up. Just my luck lol.

 

Im thinking if it becomes reoccurring issue I will have it towed to dealer where I bought it. They have a policy that if I bought a car from them all labor is free. Although an alternator change isnt that hard. Especially since this one sits right on top. Im going to have them look at it. Hopefully it was just something minor. Its pouring rain today so im gonna crack out the contact cleaner and go through those connections tomorrow.

 

Last time I had an alternator going out. The battery light would randomly come on and shut off. Then it one day while driving everything shut off. Car would just run, no tac, no radio nothing. With my hyundai Im not even getting a single battery light flicker, or any other warnings. Its weird.

 

I have been attempting to see how I could create the condition you experienced.

When you first turn the key on all the dash lights come on as part of the system's bulb check then when the engine is started most go out. The idea now is to determine what tells the system to turn off all the unnecessary dash lights.. This could be an intermittent connection originating in the interior fuse panel where the output of the alt is keeping the ign system powered so the engine continues to run.. There is usually a power control relay in the PCM that is activated by power from the ign sw. If that relay were to lose power momentarily the dash lites should come on as a bulb check , but the engine as stated could keep running.. When the power is returned all the lights go back out as if the engine started running again. . This would lead me to suspect a possible poor/ intermittent connection in a fuse panel or what powers that power relay in the PCM.
If anyone has a better possible explanation. , let's hear it ! If you take it back to the dealer you might inquire if they have a tech who could say if this was possible or not.
You never know , it could be why the former owner traded it because they couldn't find the cause and now it is your problem.

 

thanks ill bring that up to them. Weird thing when wiggled the wire on alt rpms jumped a little not by much. So maybe some cleaning the connectors? I live on gravel road so idk if that might matter. On a side note went 50+miles today with no errors. Its weird. Ill keep looking and clean terms tomorrow.

 

There really should not have been any change if the connection was good. If it was not , that would explain why the RPM's went up because you removed the load from the alternator and it just stopped charging momentarily.. Good move you may just have stumbled on to something.

 

Sorry I thought I updated this sooner. Some of the electrical I was having stemmed from the dealer installing a battery that was too small for my car. I cant remember the exact specs of the old battery. I installed the right battery and haven't had any issues. What im led to believe had happened was the old battery couldn't handle the load from the alternator and caused a cell to fail. The "dash reset" happened about the time the battery started failing. Sorry for the 10 month late response but hopefully it helps someone in the future.