I was driving home today from work, going 70mph, and my electrical system started going wild. My radio started shutting on and off along with my A/C unit. My headlight came on, my heads-up display kept flickering on and off, I received a message saying service anti-lock brakes, service traction control system, and battery voltage high (It was like 17.5!). I tried to switch to competition mode cause I was worried my brakes would lock up or something cause of the messages and I wasn't able to. I got off at my exit and all of a sudden everything went back to normal. My battery voltage dropped back down to 13.5 or so, headlights went off, everything was fine all of a sudden. It still shook me up though.

Has this every happened to anyone else? Does anyone know what the cause might be and should I be worried in the future? I had a check engine code come on a couple of weeks ago, P0175, and then it went away all of a sudden when I started it up for work. I've had the car for two years and never had problems with it until I took it to the Chevy dealer to have the thing installed for the recall they sent out on servicing the active handling system. Now I've had a check engine light come on and this today. It could just be a coincidence, but I'm still wondering what's up?

I have a supercharger set up on the car done by East Coast Superchargers and a borla exhaust.

 

So does anyone have any advice on what might of happened here? Was it just a weird glitch (after all it was Friday the 13th) or is it something I should be really worried about?

Has it ever happened to anyone else anyway? I searched the forum for it (key word was high battery voltage) but didn't find anything that seemed related.

 

Sounds like a ground is loose. Check the battery cables and connections to the chassis, etc.

 

Alright thanks. I already checked my battery out as that was the first thing I thought it might be. Everything seemed fine, but I'll check again and I'll check the ground on the chassis to see if I missed something.

On another topic I read your post "Warning for 6-speed owners" and I immediately bought the bushings from Corvette Central. Great write up and I hope it improves my shifting as I imagine mine are worn out as well. Thank you for helping improve the Corvette driving experience for all of us.

 

I've had 2 alternators die and they both produced wacky DIC messages. The second one settled back to normal for a couple weeks before it died for good.
Keep an eye on the voltage and best of luck to ya.

 

Sounds like a diode or the voltage regulator inside the alternator may be going out. The voltage regulator is responsible for maintaining the proper voltage, and this is the only thing that can make the voltage get too high. The previous suggestion to check all the ground points is also good advice. While you are in there, check any connectors or connections to the alternator and make sure they are solid.

 

I've already had one alternator die. It was working fine, but it started making a weird noise like something wasn't right. I replaced that and this is my second one now. That's kind of what I'm wondering though if the supercharger was putting too much drain on it and it's causing them to go bad really quick? I'm checking out all the wires to the battery today and if everything looks good I'll keep driving it. I don't want to get stranded somewhere though, so maybe I'll just replace the alternator and see if that does it.

 

All the wires to the battery checked out alright. They are all hooked up nice and tight, and there isn't any corrosion around the connections.

I took it for a spin yesterday just up the road to get some beer for a party and everything ran fine. No problems.

Today I took it to a friends house which is about a 30min drive and on the way there it started to do it again. My voltage climbed to about 16.5 anyway. As soon as I got off at my exit though and came to a stop the voltage dropped back down to 13.5. I was going 70mph before then and most of my driving was on the highway. It was a slow climb to the 16.5 though, it didn't actually reach that voltage until just before I got off the exit. My gauges were all fine when my voltage was at 16.5, with the exception that it said I didn't have my seat belt on. I did have it on though.

On the way back everything was fine. Nothing abnormal was happening.

I ordered an alternator off ebay just in case. (They were only about $190 shipped which was a lot lower in comparison to what GM sells at 300+). I hope the new alternator fixes the problem. I will keep driving it until the alternator comes as this is the only car I have at my location. I'm 6 hours away from my parents house where my other cars are, so I don't have much of a choice.

I'll update this post then also if any changes occur just in case someone ever needs to reference it.

 

So this is just a follow up to my earlier posts in case anyone ever uses this for reference. I replaced the alternator and it solved the problem of overcharging. I haven't had it charge that high again anyway.

However, I seem to still be getting the message "service charging system" and I do notice that every now and then my voltage drops to around 10. Mostly this occurs when I'm running something else like my heater or a/c and am stopped somewhere such as a red light. It goes back up to the norm, 13 or so, when I start driving again. I'm not sure why this is occurring, but my car seems to be running alright still.

Perhaps the overcharging problem I had earlier ruined my battery or something else? I'm not entirely sure. Perhaps this is even the norm, but I've never noticed it before. As long as I don't break down anywhere I figure I am alright. Replacing the alternator has so far not caused my car to overcharge and I have driven it quite a bit, including several 3 hour + trips.

 

I would suspect the battery. When the battery is fully charged, it should read about 12.6v and running about ~13.0v.