Chasing Low Voltage
Thread Starter
Intermediate
Joined: May 2021
Posts: 28
Likes: 2
From: Ormond Beach FL
Chasing Low Voltage
2006 Z51 convertible, 105,000 miles, no mods
WHAT I LEARNED: the voltage output from the alternator reads low when the alternator is charging amps at high level.
To start i have been having low voltage readings on my DIC for about a year. After reading multiple comments on this site and my own knowledge about these things I tried several solutions.
First, I verified all wiring and connections. Local auto store said battery and starter look good.
Then I found the starter terminals were bad as suggested by many. At this milage I expected this. The starter was replaced. Things seemed to look better but it didn't last.
Second, I tried the alternator as suggested by many. The output varied, so a new alternator is installed. It turns out I didn't need it but at the milage I figured it was good to change it.
Finally, it would not start, and battery voltage showed 11V.
I said all that to say this...It was the 2-year-old battery all along. A new battery is installed, and all the voltage drops are gone.
Update: The old battery was bad but new battery was not total solution. So, I hooked my VOM to the bat plus and frame grd. DIC and VOM did not agree. DIC reads about 3 to 4 tenths lower than VOM. Heated engine up and DIC went into the 12.5 range while the VOM showed 13.01.
I suspect the analog gauge on the gauge cluster and DIC is getting input from the ECM. I'm out of wires to chase.
Anyone with a schematic or information on where to look next would be appreciated.
thanks
WHAT I LEARNED: the voltage output from the alternator reads low when the alternator is charging amps at high level.
To start i have been having low voltage readings on my DIC for about a year. After reading multiple comments on this site and my own knowledge about these things I tried several solutions.
First, I verified all wiring and connections. Local auto store said battery and starter look good.
Then I found the starter terminals were bad as suggested by many. At this milage I expected this. The starter was replaced. Things seemed to look better but it didn't last.
Second, I tried the alternator as suggested by many. The output varied, so a new alternator is installed. It turns out I didn't need it but at the milage I figured it was good to change it.
Finally, it would not start, and battery voltage showed 11V.
I said all that to say this...It was the 2-year-old battery all along. A new battery is installed, and all the voltage drops are gone.
Update: The old battery was bad but new battery was not total solution. So, I hooked my VOM to the bat plus and frame grd. DIC and VOM did not agree. DIC reads about 3 to 4 tenths lower than VOM. Heated engine up and DIC went into the 12.5 range while the VOM showed 13.01.
I suspect the analog gauge on the gauge cluster and DIC is getting input from the ECM. I'm out of wires to chase.
Anyone with a schematic or information on where to look next would be appreciated.
thanks
Last edited by Vette_Beach; Aug 31, 2022 at 04:08 PM. Reason: update
Retired & lovin' it!
Joined: Mar 2005
Posts: 4,471
Likes: 543
From: Jackson NJ
C6's seem to eat batteries like crazy. First step with any electrical problem is to suspect the battery, no matter how fresh it may be or even if it tests good (allegedly).
You don't mention if you use one, but a battery maintainer (not a charger) regularly in use overnight, will save a lot of grief.
You don't mention if you use one, but a battery maintainer (not a charger) regularly in use overnight, will save a lot of grief.
