Ok so I was driving on the freeway and when I exited my car would not go just revved up.. so I took the key out and restarted it.. and the shifter wouldnt go into drive, so I took the key out put it in the little slot to put your car in drive, put it in neutral, started the car and it would only go In d1, then was driving and when I stopped my car completely died. There was no power to the accessories (the lights were suuupperrr dim and the radio wouldn't turn on) but when I cranked it there was one little click then alll the power was gone... And when I checked the battery it was at 4v and dropping but when the batteries disconnected it goes back to 12v but immediately after connecting it, it drops strait to 6v and drops... I've disconnected every sensor, every fuse... Battery voltage seems to stay steady when I disconnect the interior light fuse (replacing it didn't help) and disconnecting the bigger harness on the fuse box under the hood.. any help would be appreciated
95 accord lx wagon A/T

 

If your car battery went all the way to 3V, it is dead. You'll need a new battery. Also, check battery and alternator cable connections, have the alternator tested.

Regardless, the battery is dead.

 

ya but once I take the cable off it goes immediately back to 12v
(And it's a new battery and alternator is good)
​​​​​​And when I disconnect the bigger harness from the under hood fuse box the battery goes back up to 10v

 

What you describe indicates the battery capacity is really low. It is deeply discharged. Going that low usually will cause permanent damage to the battery.

 

I just tried a good battery right now and it did the same thing dropped immediately (and I mean under a second) to 4v and immediately after disconnecting it rapidly goes back to 12v.. maybe a short somewhere?
I'm also getting continuity on the (VCC (sends power to sensor) from the ECU to the fuse box) idk if that's normal or a short

 

How are you measuring the voltage? Where are you connecting the test leads to?

 

im doing a straight voltage test on the battery and it's 12v disconnected and goes down to 3v upon connection

 

Where are you connecting the test leads to? Where are you connecting the black test lead to? The battery post or car's chassis?

Try measuring the voltage both ways, black test lead on car's chassis (such as ground bolt) and negative battery terminal. Are they the same measurement?

 

Yeah same both ways... I disconnected the bigger harness from the under hood fuse box and the voltage went up to 10v but once I put the key in and try and start. There's one little click and my battery is down to 3v.. also my radio won't turn on at all even with full charge

 

If its a short would replacing my whole engine harness maybe be the solution ?Cos none of my harness wires are protected at allll

??

 

That would be a serious short to pull a new and fully charged battery to 3 volts.

Do you get a massive spark when connecting the terminals to the battery?

To be that large of a current and not blow a fuse it would almost have to be a short on the large gauge wire from the positive terminal to the starter. No fuse on that link.

Also wanted to add if there is aftermarket stereo equipment installed in the trunk and there is a large gauge wire run from the positive terminal to the trunk through the firewall with no grommet or fuse. That would be my primary suspect. Where the firewall has chafed away the wire insulation and is now shorted to ground.

 

No there's no spark at all just a massive drop. I've chased all the wires and can't find any melted, cut or chaffing wires... Could it be just the underhood fuse box is bad? Because when I unplug the big harness on it it stops the current drop and when I disconnect the middle brown one (with the bigger wires) it goes back up to 11v

 

So there's slight power inside the car (dim dash cluster, still no power whatsoever to the stereo), and when I turn the key, there's a click and all the lights go off

 

Also before it had just died the speedometer and tach were bouncing around or just didn't work, and the gas gauge would randomly just drop below E, could there maybe be a short going to the cluster?

 

SOLVED
I put in a new engine harness and it started up