Low Voltage?

[Custom88]

I noticed tonight my headlights dimming excessivly at idle tonight so I monitored my voltage. While cruising it is 14.5 volts. When the engine idles, or I'm coasting it drops into the low 12 volt range. If I'm idling and turn on heated seats, defrost, rear defroster, and just the headlights, the voltage drops down to 10.8. Does this sound normal, or no? The engine starts to idle roughly with all accessories on and idling.

[macadamiaman]

wow that's LOW! Not normal at all..

I'll turn on everything to duplicate and see. My idle is about the same, but cruising I've never seen it go below 12.5v - like when I'm TRYING to get the volts to go down, with all four windows down and stuff. I'll doublecheck tomorrow though if I remember...


..you think low volts cause the problems you have? While I know regular bulbs do not like too much electricity, the car has mostly LED lights, so how do those deal with too little electricity?

[Aurora40]

No, that isn't normal. Did you ever investigate your belt slipping due to your overly dragging A/C compressor?

10.8 is like stall-out range. I'm not surprised the engine starts to idle roughly. You have to be careful because if it does stall out, it might not crank up again due to discharging the battery. If the battery is healthy, it will be providing a lot of juice at idle and might not be up to the cranking task.

I would suggest first checking the battery, as it may be going and thus becoming a voltage dump which is impacting the rest of the electrical system. If it's original, it'd be going on 5 years old now.

[Custom88]

The battery was dead when I bought the car so I asked the dealer I bought it from to replace it for me, they said they put a brand new GM battery in to the tune of over $100. The car takes atleast 2-3 seconds to start each time I start it though. with no accessories the voltage is fine, it just can't keep up when I turn teh accessories on obviously. What is an acceptable range? Thanks.

I donj't know how you could check for the belt slipping? How would one go about doing this? THe dealer on the AC issue said don't bring it in until something goes wrong.

[byro3227]

From the sounds of it should not be your battery. The only thing that I can think of is the altenator. If it is working properly then you should have a reading of 14 to 14.5 volts (what my car reads) If not the reading should only be around 12 volts meaning that your battery is being drained. If you think the meter in the car is wrong or just for a second opinion you can always borrow a voltmeter and get a second reading.

The previous car I owned (Chevy Corsica) had the same symptoms you describe. I was driving along and the battery light came on and then stalled. I performed the test I described and sure enough the alternator was not recharging my battery.

Hope this solves your problem or at least helps

[macadamiaman]

Yeah, I can put on both heated seats @ high, rear defrost, A/C up all the way @ 60 degrees, all windows going up at the same time, head lights/fog lights, etc... and it doesn't go below 12.6v

Without the windows it won't go below 14.3v. Wow, windows take a lot of juice.

Anyway yeah, you've got yourself serious electrical problems. Get it fixed while the warranty's still on. Something has gone wrong - convince them - don't let them turn you away.

[TJM]

Alternator - even with a toasted battery your voltage should be above 12. the voltage regulator is built in to the alternator; sounds like that's it.

[littleevil]

I have about the same problem. I notice mine driving down the highway and the volts drop in the 12 range and my headlights flicker. I notice it more with everything electrical running. Sometimes the car will be fine for a few days, but when it happens my engine light will be on for a crankshaft sensor code and my car will not start for like the first 10-20 attempts, kind of like a dead battery. There was a TSB on the alternators that would cause them to cut out leaving your car on battery voltage for a second, and a new alternator was designed.

So far I replaced the alternator, batery, ignition switch, crankshaft sensor and cleaned up my grounds. And nothing helped, looking at the ground from the front right of the car by the fender, my ground cable was very corroded and the wire itself looks green inside. So the next thing I'm trying is to replace that ground cable.

[BNICOV]

Oh you'll know when the belt is slipping. It screeches like mad. Pretty much any car once you crank up all of the accessories has a bit of a hard time keeping up with the demand. 12.5-14.5 volts with everything going would be acceptable. It wouldn't hurt to check the grounding cables to make sure they are not corroded.