99 C5 Volt meter jump
Thread Starter
5th Gear
Joined: Jul 2003
Posts: 5
Likes: 0
From: Toronto
99 C5 Volt meter jump
Hello,
I have a 99 C5 and I noticed that when I turn my signals on the volts can jump down from 14.3 to 13.7 even lower but when I turn the signals off it returns back to full charge. Alternators works fine and Battery is new at tested perfect. Is this something that happens on others C5 ?
I have attached a video of what I am seeing and want to confirm if others have the same experience. thanks
I have a 99 C5 and I noticed that when I turn my signals on the volts can jump down from 14.3 to 13.7 even lower but when I turn the signals off it returns back to full charge. Alternators works fine and Battery is new at tested perfect. Is this something that happens on others C5 ?
I have attached a video of what I am seeing and want to confirm if others have the same experience. thanks
Instructor
Joined: Oct 2021
Posts: 180
Likes: 42
From: Raleigh
Maybe a bad ground connection somewhere. I've heard there are something like 7 ground connections in the C5. It sounds like that circuit is drawing too much current, but no so much to trip the fuse. The problem could be anywhere in the circuit: ground connection, power line, bulb, etc.
Instructor
Joined: Oct 2021
Posts: 180
Likes: 42
From: Raleigh
I just checked mine with the engine not running. The volt gauge on the instrument cluster does not move at all when using the turn signal. I do have an aftermarket volt meter on the A pillar as well with better resolution. I see it drop about .1 volts when the turn signal is on.
Thread Starter
5th Gear
Joined: Jul 2003
Posts: 5
Likes: 0
From: Toronto
Ok thank you....thats what I wanted to confirm. I did change my headlights to an after market non-pop up solution. So I am suspecting that might have something to do with it. If I push it and let it flash for several minutes it doesnt seem to hit the battery at all. Just the volt meter going nuts in the DIC....I also have a volt meter at the battery and thats just solid with no matching draw. Maybe I dont have to be so paranoid about it
Instructor
Joined: Oct 2021
Posts: 180
Likes: 42
From: Raleigh
I'm not sure checking voltage at the battery determines anything other than verifying a weak battery is the culprit. After a quick look at the wiring diagrams, which vary by model year, it looks like most of the turn signal circuits are hanging off the instrument cluster panel block. I don't see the voltage gauge specifically called out anywhere in the wiring diagrams. So it's probably safe to assume the voltage gauge is measuring voltage somewhere within the instrument cluster. You could measure voltage at different points in the circuit based on the wiring diagram to isolate where the voltage drop is occurring. But if it's inside the instrument cluster itself, IDK if you'll get to the root cause.
Thread Starter
5th Gear
Joined: Jul 2003
Posts: 5
Likes: 0
From: Toronto
Ok thanks for the intel. Im guessing with adding after market items to the circuits (turn signals) I am sure its drawing a bit more that usual. Hence the more eradicate behaviour that your standard bulbs. I wil just keep an eye on it. It doesnt seem to be impacting anything else at the moment. So hopefully it wil stay that way 
