LS4Monte

Hey guys. I am having a electrical problem with my '07 Monte Carlo SS.


When the car is running, randomly the battery voltage (as shown on my aeroforce gauge) will start jumping all over the place. It will drop from 14 volts down to 12.3 or then back up to 14.5 then 13.8 then down to 12 and then 14 again and so on. It's all over the place and while its doing this I can see all the lights inside and outside dim when it drops.


I have changed the alternator, battery, and made sure connections and grounds were clean and tight. I tried unplugging the battery voltage sensor, and it made no difference. I don't know for sure if that is a good or bad thing unplugging the sensor made no difference...


Any ideas? Is it worth trying a new voltage sensor?

Mike The Canadian

I think our cars do that by design, the alternator regulates the voltage and output isn't consistent.

Someone with more experience on these cars electrically will chime in I'm sure.

You could also do a big 3 upgrade to the elec system.

LS4Monte

It wasn't an issue before though so something can't be right. I have come out from work twice the past couple of months with the battery being dead, which is what made me decide to do a new battery and alternator. The battery I had in it was a Delco one that was almost 3 years old.


Anybody ever have to change the voltage sensor before?

Killerb

Something is not right with that, you need to have your alt and battery tested in the car for load and diode issue.Possible connection issue but don't take it to a AZ or some parts place, take it to a real repair shop. Checking grounds is a must

superglide9375

Where did u hook up that gauge and did do it before that change?

LS4Monte

The gauge was plug and play in the OBD port with this car. No extra wiring. I have had the gauge over a year before I started having this problem over the summer.

LS4Monte

I think I'm going to spend some time again just going through all the grounds, connections and looking over the wiring.


It was doing it again today. Out cruising on the highway, I look and the Batt volts and they dropped down to 12.8 and stayed there. Looked again maybe 5 minutes later and it's back up to 14 like it should be...

Mike The Canadian

My Super does this all the time, when I'm cruising the voltage is between 12.8 - 14.

Let me know if you find anything, perhaps I have an issue that's being covered up by having a deep cycle battery (hence not finding it dead).

Sint3k

I would hook up a scan tool and watch the pulse width that is commanded of the alternator, you will see if it's the computer doing it or not.You can also manually ground the alternator to make to run 100% power to see what output you get. The alternator does manage voltage, but does not mean you won't see battery voltage when the alternator is commanded a low duty cycle. Also, don't be fooled by voltage gauges inside the vehicle, make sure you are reading directly from the battery, or at least compare the voltage to make sure whatever you are looking at is accurate. Also I've run into a problem on the ground connection near the batter where it has corroded internallycausing intermittent no start and voltage fluctuations. I ran 0 gauge wire "big 3 upgrade"since I was there anyways