Help! Battery Fully charged but car is D E A D.. dead!

[yello80vette]

I installed a new starter in my 1980 last summer. It has a rather new, fully charged battery.
The car sat for a few weeks without being started. When I went to start it, the engine began
to crank then it seemed the battery was weak and it died. I thought it was no big deal so I
charged the battery.
I got in, put the key in the ignition, turned it and the buzzer sounded very weakly for a few
seconds but the ignition did nothing. Then the buzzer went dead. No lights, no power to anything.
What could have caused this? Anybody? Help?!

 

[LLC5]

I installed a new starter in my 1980 last summer. It has a rather new, fully charged battery.
The car sat for a few weeks without being started. When I went to start it, the engine began
to crank then it seemed the battery was weak and it died. I thought it was no big deal so I
charged the battery.
I got in, put the key in the ignition, turned it and the buzzer sounded very weakly for a few
seconds but the ignition did nothing. Then the buzzer went dead. No lights, no power to anything.
What could have caused this? Anybody? Help?!

What is the battery voltage at the battery when the problem is active? Before doing any work, make sure that the battery has been properly load tested and that the battery cables are clean and tight on the terminals. Good luck with it.

 

[Rod75]

I agree with post above!
Pull the battery out and return it where you bought it. They should be able to test it out for you. Go from there...
Good Luck

 

[LanceB]

My 81 goes dead all the time even if I don't drive it after just a couple of days. I assume there is a slow drain somewhere but I have not been able to locate it. I finally got a battery quick disconnect and undo it even if I am walking into the grocery. Its kind of a PITA to reset radio stations all the time (and seems kind of bubba-ish) but since I started doing this 2 years ago I haven't needed a battery nor have I been stranded. Maybe one day I can locate the gremlin but multiple new starters, batteries and alernators weren't get it done.

For what its worth I recommend inspecting all the wires going from the battery to under the hood and especially check ground is clean/tight.

 

[yello80vette]

Noooope. Not that.

I had the battery tested and they said it was in excellent condition.
Now listen to this one. With the battery removed, I hooked jumper cables
up directly from another car to the pos. & neg. battery cables.
It did the exact same thing. Turn the key to the on position, the buzzer
starts buzzing and the gauges jump to life. Then I turn the key further for
the ignition, the buzzer dies and the gauges go dead. Turn the key again
and nothing. The cables are in excellent condition. Connection to the starter
is tight. Did the 1980 come with gremlins as an option?! :confused

 

[Peer81]

Here is what I would do.

As you already checked the battery. I myself have a very nice fully charged optima yellow thing that couldn't even crank the engine ones. Swapping battery's or even better hook an extra on with jumpercables. If you're sure that isn't the problem then move to the next.

Several posibilities.
- ignition switch bad?
- neutral safety switch bad or with manual clutch switch bad?
- any orginal or after market alarm in the way?
- maybe something else?

You can check if it's any of these 3 by short circuiting the starter from the big power cable to the small 12v connection on the solenoid. By very carful when doing this and make sure the car is in Park! If the starter works then the problem is somewhere in the signal wire from the fusebox to the starter solenoid.

Best way to tackle this:
Take a look at your wiring diagram in your service manual. If I'm correct power for the ignition switch comes from the 2 fusebly links that connect to the starter, are they attached the right way?
Your ignition switch (on top of the steering column) has a seperate pin for the 12v that goes to the starter solenoid (in the wiring diagram it's called sol at the ignition switch). You can check the switch if it gives 12v to the starter when in the start position. On my 81 it's the yellow wire (don't ask me how I know :ugh).

If this is oke move to the next or begin with this in what order you like...
The neutral safety switch on a automatic located next to the gearlever under the console, if this is broken or had a bad contact 12v wouldn't reach the starter solenoid. To quickly check you can bypass the switch with a cable by "shorting" the 2 poles from the switch connector. On my 81 yellow and purple wires. Manual transmissions have the same principle switch but at the clutch under the dash, same test can be done.

From the safety switch a wire (purple on mine) goes to the original alarm relais you can check for 12v on the incomming wire. You can also bypass this relais but make sure you have the right outgoing wire. If you have an aftermarket alarm make sure the fuse is still good and if it's on in the off position when you want tot start the engine. As far as I know from the original alarm relais one or two wires go directly to the starter solenoid.

Maybe something else? You can folow the wiring diagram wiring from the ignition switch to the starter solenoid, maybe your 80 has some other features mine doesn't that you can locate in the wiring diagrams.

I would begin with the easy part and that is the neutral safety switch. And btw, normally it's not something very difficult so I hope you don't need any info from this reply.

Greetings Peter

 

[SVO]

Bad battery cables. You need to swing under the car and check for bulging of the cables, which indicates internal corrosion of the cables. Also check the ground cable that runs from the engine to the frame.

 

[yello80vette]

Thanks. I'll check that today. I'm willing to try anything. This was a Sears Diehard battery which is all I ever buy for any car. It was 3 years old so I took it back and they did a test on it and said it was bad. I got a brand new one, took it home and installed it. I hit the horn button and "BEEP!" I thought "What a relief. All it was was a bad battery!" Then I got in and turned the key and it did the exact same thing. My heart sunk.

 

[yello80vette]

Negative battery cable was severely corroded. More than half of the copper wires were disolved or broken.
Bought a new one at Advance Auto, installed it and the car fired up stronger than ever. This made my
weekend! I'm so greatful to SVO. Thanks a million!

 

[Peer81]

Great to hear the problem is fixed!

Greetings Peter