Hello everyone, I am Christian, new to the forums. I am the owner of a 2000 corvette with 70k miles.
I bought my car last year and it already had some electrical issues with the fuel gauge and the voltage gauge. Everything on the car works fine minus those two. I already tracked down the fuel issue to the fuel transfer on the gas tanks.
The problem I am experiencing is intermittent; when i put the key on the car into the on position all the gauges go up and down normally but then the voltage gauge goes to 0.7-1. Sometimes randomly with the car on or off, the voltage gauge will comeback to life normally and the seat belt light will start flashing. This makes me suspect that whatever is happening is related to that part of the cluster given that both the seat belt light and the voltage gauge are together and if one works the other too. Normally, if I try to read codes from the DIC, the diagnostic message would appear for a split second and go away. On those instances when the voltage is working properly (which is very rare and happens for less than 10 seconds) the DIC lets me read the codes. I already checked every ground on the car, cleaned all grounds on the engine bay, on the doors and on the back of the car. I already checked the fuses related to the cluster and already repaired the ignition switch. As a last resort, today I pulled out the cluster and using a this diagram (https://corvetteforum.shelor.net/Dia...PC_Pinout.html) tested every single circuit. The pin that goes to the positive battery voltage reads 12v as expected when using g104 ground.
At this point I suspect it is an issue with the cluster itself, the BCM seems to be okay since everything else works on the car perfectly fine. I know the fuel gauge issue is unrelated because when I disconnect the battery and connect it again the fuel reads fine until I start driving. I tried searching other threads for months already and nobody seems to have this exact same issue. Whatever is happening with the voltage gauge is responsible of the seat belt light flashing and not being able to read codes from the DIC or from the OBD2 port.
I also want to add that the key fobs that came with the car do not work, they seem to be the original ones. When I try programming the key fobs from the DIC, the car prompts me to press lock and unlock buttons at the same time but when I do nothing happens ( more than 11 seconds). I think this issue could also be related.
Thanks for your time.

 

Most basic question but I didn't see it listed:

With a multimeter / DMM, what is the voltage as measured across your battery terminals when: 1) the car is off and has been sitting for a day or two; 2) the car is cranking as it fires up; 3) the car is cold idling, and 4) the car is hot idling?

 

The one thing that some people overlook is the relays, because the Ignition switch contacts are not made to carry all the current that is required there are relays that are powered by the Ignition switch and those relays contain the higher amperage rated contacts, and then again it could be your dashboard itself.

 

Hello, thank you for your response,
1)My battery is at 12.8 when off, the battery is new.
2) Will test this, but even if I let the car sit for days it always cranks up fine.
3 and 4) around 14.3-14.5
Does not seem a problem related to the alternator or battery though, I rebuilt the alternator around 2 months ago, one day it stopped charging the battery at all and the DIC displayed "charging system error"; once I got the alternator rebuilt never had a problem with that again When I bought the car it had a lot of electrical gremlins but none of them were related to the other (which I am glad).

 

Hello @mmartinez, if it was a relay, do you think the connector at the cluster would give 12V? I checked fuses 19 and 25 at the passenger footwell and both are 12v. If I am not mistaken fuse 25 should be the one that carries the voltage to the gauge.

 

Did you Ever figure out what caused this?