I have a 2000 Corvette 6 speed. Yesterday I went to take it out after sitting for one week. It started right up. After running for less than 1 minute, the DIC which was set on Battery Voltage and started out at 14.2, started to fluctuate. I saw it go down to 9 volts for a second and then the car died. I went to restart it and it clicked once then started right up and seemed to be running fine. I also noticed while driving last weekend, the battery voltage on the DIC fluctuated between 14.2 and 13.0 while driving. The analog gauge on the dash, I would have never noticed anything. Anyhow, I was somewhat concerned, but the car ran and drove fine. That was last weekend, now back to yesterday. Like I said, after I restarted the car it appeared to be running fine. Yes, I was leery of driving it, but I got about 3 miles away and it died. It restarted again, but was running rough and died again. It restarted again but I could not keep it running. The DIC showed "LOW VOLTAGE" I got a ride home and came back with another battery (it showed 12.7 on my VOM). The car cranked normally for about 3 to 4 seconds and started - but I soon realized it was running rough. It would die and restart, but could not keep it running. The LOW VOLTAGE message came on the DIC again. Since then, I have had that battery out of the car and it measured 12.7 on my VOM. Towed the car home. It turns over fine, but doesn't even fire. The headlights are bright, horn is loud, when I turn the key, the seat belt light and check engine light come on but they are dim. Again, the LOW VOLTAGE message appears on the DIC. I use my handheld VOM to test the battery with the cable disconnected - it reads 13.1, When I connect the battery cables - it jumps everywhere from 0 to 13 volts and is constantly changing! ??? I attempted to read the "codes" on the DIC. When I turn the key on to "run" - Corvette by Chevrolet and then the mileage flashes followed by nothing. When the key is shut off - the DIC show LOW VOLTAGE. I hear a buzzing / sizzling sound from the #35 relay (fuel pump) I do not hear any sound from the fuel pump itself. I am confident it is not starting because of the lack of fuel - but am at a loss on how to proceed. Hoping that someone can shed some insight on this.

 

Sounds like the ignition switch is bad.

 

am going thru all the grounds and checking for problems there.... so far no problem found.

 

I cleaned the grounds at the G104 - no change.
I checked the cables on the positive stud in the underhood fusebox -- no change.
Battery is a full charge when disconnected - BUT - when cables are connected to the battery - it measures from ZERO to 13-- constantly changing. With that occurring - I have not even attempted to start the car now.
There are 2 heavy gauge red cables connected to the stud on the underhood fusebox. One goes to the battery and one to the firewall (I assume it goes to the interior fusebox) IF I remove that cable that goes to the firewall, and connect the battery terminals -- I get a steady voltage (12.9) Therefore, I am concluding that it must be something with that cable.... or in the interterior fusebox ---- ANY INPUT?????

 

If you connect the battery cables and the battery voltage immediately drops badly then I would suspect the battery. Get the battery load tested to ensure it is good. Many parts stores will do it for free.

 

I went through what your symptoms are recently. Was a weak battery after load testing it. Brand new battery did the trick.

 

The same thing happened to me. It was loose and corrodedpositive cable leads from the battery to the alternator. Where they meet at the starter solenoid.

 

after switching the battery out ---- everything is hooked up again --- and battery is constant at 12.7 -- i go to turn the key and I notice that I DO NOT hear the fuel pump prime -- and I hear a buzzing noise from the relay in the under hood fuse box for the one marked fuel pump. I also, notice that the horn relay is the same number -- so I swap that relay and still have that problem - and the horn works fine. Also, same as before when the ignition key is on - the check engine and seat belt lights are on but very dim. no other idiot lights come on. What causes a relay to BUZZ like an old fashioned hand buzzer for about 2-3 seconds. Now to determine of the problem is the fuel pump or the if is not working because it is not getting power.

 

Like I posted before, it can be the ignition switch when the constant power fuses have good voltage but the switched power fuses have low voltage.

 

I would rebuild or replace the switch. They are not terribly expensive. The rebuild instructions are posted and that is free.
https://www.corvetteforum.com/forums...ch-repair.html

 

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That is making more sense to me now --- when I get home tonight --- the ignition switch will be my focus -- thanks

 

Thank you LionelHutz and the rest here on this forum. Not only the advice and troubleshooting - but Bill's awesome and concise instructions allowed me to tackle this repair myself. Replacing the ignition switch was the problem and so far -- all is well again with my C5..... until next time......

 

 

hmmm...having a very similar problem, glad you got it worked out!

 

My problem was the ignition switch too. I cleaned grounds, replaced a battery etc., and finally gave in to my expert mechanic who quickly diagnosed a bad ignition. A new ignition did the trick! Have the bad one if anyone wants to rebuild one. that’s beyond me