Complete Electrical Failure?
Thread Starter
Heel & Toe
Joined: Jun 2023
Posts: 17
Likes: 4
From: Orlando FL
Complete Electrical Failure?
Hey all, so I tried to start my C4 93' today, and as soon as I put the key in and turned it, everything shut down. Meaning it seems all electrical just stopped. No lights are on, windows don't work, the car doesn't crank, the dash lights in ACC mode don't show. Its as if there isn't even a battery in the car. Everything that had been just fine with it since I purchased it back in February, and I actually drove it earlier today. I checked the battery and it shows 12vDC. I disconnected the battery negative and reconnected it, and still nothing. I checked all the fuses, both inside the car by the passenger side as well as the large fuse box thats next to the battery itself, the one with the large fuses, all looks intact.
I installed a new Jensen Stereo, and used the Metra amp bypass harness, and it has been working quite well the last 2 weeks (minus some whine, which I was going to try to get to soon), but not sure what happened all of a sudden. Any ideas? Anyone else come across this? Again the Battery shows 12vDC but its as if the car is behaving like it has no battery installed at all. Thanks in advance for any insight you all might have or a similar experience you can share.
Thanks
Kunal
I installed a new Jensen Stereo, and used the Metra amp bypass harness, and it has been working quite well the last 2 weeks (minus some whine, which I was going to try to get to soon), but not sure what happened all of a sudden. Any ideas? Anyone else come across this? Again the Battery shows 12vDC but its as if the car is behaving like it has no battery installed at all. Thanks in advance for any insight you all might have or a similar experience you can share.
Thanks
Kunal
Melting Slicks
Joined: May 2014
Posts: 2,895
Likes: 592
From: New Port Richey FL
Drifting
Joined: Jun 2013
Posts: 1,965
Likes: 343
From: Shell Point (Crawfordville) Florida
A fully charged battery should read 12.6 V. A reading of 12 V is a battery that is only 25% charged. How old is this battery? Voltage and amp-hr. capacity are two different things. The first thing you need to do is to charge up the battery and then go from there.
And you are going to have to search for a parasitic draw causing only 12 V. Maybe you did something in your wiring that caused this. Check your battery connections like Agent 86 said but you are lucky if that's your only problem.
And you are going to have to search for a parasitic draw causing only 12 V. Maybe you did something in your wiring that caused this. Check your battery connections like Agent 86 said but you are lucky if that's your only problem.
Last edited by mrlmd; Apr 12, 2025 at 08:05 PM.
Melting Slicks
Joined: Oct 2003
Posts: 2,189
Likes: 830
From: Chapel Hill NC
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 C4 of the Year Finalist - Unmodified
2025 C8 Stingray of the Year Finalist - Unmodified
If the battery checks out and the connections at the battery are good Id check the negative battery cable and its ground connection.
Thread Starter
Heel & Toe
Joined: Jun 2023
Posts: 17
Likes: 4
From: Orlando FL
I gotcha, will do. I checked the negative to the battery and it was good, but didn't check any of the ground contacts. I did find in the FSM that there are 2 Fusible Links, both appear to be coming off the Alternator. I wonder if those blew. As I understand from the document, the Fusible Link is the main breaker for the entire electrical system. But the starter is directly connected to the battery and the car doesn't even crank. I was going to pickup a new Battery, and search for that fusible link and go from there. Appreciate all the insights guys! Will report back with what I find out.
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Easy way to test if it's the fusible link. With the battery installed check for voltage at the starter. The key can be off. The main cable going from the battery to the starter should show 12vdc all the time. The fusible link is in-between the battery and the starter. So if you have 12v at the battery but nothing at the starter you have a blown fusible link or a broken cable.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Jun 2013
Posts: 1,965
Likes: 343
From: Shell Point (Crawfordville) Florida
Did you try and recharge the battery? 12 V is not a charged battery - it is 75% discharged..You may have a bad battery with a dead cell. You can measure the voltage of each cell (should be 2.1 V each). Until you have a working battery all bets are off to find a solution at somewhere else.
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
Did you try and recharge the battery? 12 V is not a charged battery - it is 75% discharged..You may have a bad battery with a dead cell. You can measure the voltage of each cell (should be 2.1 V each). Until you have a working battery all bets are off to find a solution at somewhere else.
Thread Starter
Heel & Toe
Joined: Jun 2023
Posts: 17
Likes: 4
From: Orlando FL
So I took out the battery, and cleaned the chassis ground connection. There was no corrosion but it looked a bit dirty and had a little rust. Once I put everything back the electrical power to the car was restored, lights turn on and engine starts and everything seems to be operational. So I guess I had a questionable ground, which blows my mind considering the vehicle ran well for the two months I've owned it. As always I appreciate everyone's suggestions and advice.
Drifting
Joined: Jun 2013
Posts: 1,965
Likes: 343
From: Shell Point (Crawfordville) Florida
Coat that ground connection with NO-OX-ID, a conductive grease, so you never have to go back in there and do it again. NOT dielectric grease - that is an insulator.
And how many volts does your battery read after running the engine 15 min? Does it charge up to 12.6V?
And how many volts does your battery read after running the engine 15 min? Does it charge up to 12.6V?
Drifting
Joined: Sep 2022
Posts: 1,486
Likes: 395
From: Liberty, SC
2023 C4 of the Year Finalist - Unmodified