Okay this is a new one on me, my battery light is on while the car is off, everything in the car is turned off. When I start the car the battery light goes off. WTF?

annnnnnd my damn oil pressure light just started flashing when I started the car a few minutes ago, not on steady, just flashing.

 

Thats because when the car is off, the alternator isn't charging. It's supposed to do that when there is no current running from the alternator to the battery.

 

No the battery light is on steady as the car just sits outside. Nothing is on, no key in the ignition switch nothing. It's definitely NOT supposed to do that.

But at the same time this just started today, I also just started having a problem with the oil light flashing. Turns out there are wires that go from both the voltage regulator on the alternator and the oil pressure switch to the same spot in the Integrated Control Unit under the dash. I'm hoping it's just that that's the problem.

See what I posted further down in this other thread: https://honda-tech.com/zerothread?id=1089059

 

I've been having a simular issue lately aswell...

With the car off, key out, my oil pressure light and battery light stay on, no door chimes, and power windows still work etc...

When I start the car the lights go out, everthing is fine both oil pressure and battery voltage...

If I unplug plug A on the ecu or anything in the IGN circut the lights go off and everythings power gets shut off...

Not really sure what's going either...

 

well the oil pressure flasher circuit, the key-in door open chime and domelight switch, and other functions are all controlled by the Integrated Control Unit behind the under-dash fusebox. When I had that unplugged today none of that stuff worked.

 

Try replacing the battery. Low voltage does all kinds of strange stuff.

 

Alright I removed the B-terminal wire (big white wire) from the alternator, and the battery light went away. Does this mean my alternator is the problem? If so does that mean my oil pressure light flashing problem that started at the same time as this is just an insane conincodence?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jlacoy82 &raquo;</TD></TR><TR><TD CLASS="quote">Try replacing the battery. Low voltage does all kinds of strange stuff.</TD></TR></TABLE>

You arent going to make it very far driving on just the battery power, if there are any other cars in your possession, try just hooking up one of their batteries to your terminals in your car, almost guaranteed the light will turn off.

 

no change when connecting it to another battery

 

im having the same problem with a volvo at my work. The customer came in with the battery light staying on even with the car off. I changed out the alternator first and then swapped a different battery in to see if that was the problem. Neither the new battery or new alternator fixed the problem.

No one can seem to figure out why the battery light stays on when the car is off. I havent gotten a chance to look at it in a few weeks but my guess is there is a short in the wiring somewhere.

 

It sounds like you could have a couple of bad diodes in the alternator, causing a drain. But I can't see how that would cause the light to come on, unless there's some kind of short inside the alternator and it's bleeding juice through the wiring harness.

Does your oil pressure light stop flashing when you unhook the alternator?

Try hooking the alternator back up, then start the car, the pull the negative lead off the battery. If the car still runs, check the voltage your getting. If it's under 13 volts, your alternator is ****.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wreckedmyteg &raquo;</TD></TR><TR><TD CLASS="quote">Does your oil pressure light stop flashing when you unhook the alternator?
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I have not tried starting the car w/o the alternator hooked up. Is it safe to do that?

 

Yea it's safe. It sounds like your alternator has a short and is feeding juice back through the wiring harness when the car is off, causing your ICU to act retarded.

When you unhooked the power lead from the alternator your battery light went out (I assume because there was no juice to bleed into the harness). Just leave it unhooked and start the car. You might want to tape it off since it's a hot lead and runs straight to the battery.

Your battery light should come on (since there's no charge), but the oil pressure light should go out (if the alternator is what's shorting). I would unhook the harness from the alternator as well.

Easiest way to see if it's not charging is to pull the negative cable off the battery while the cars running and check your voltage. It should be 13-14 volts at idle.

 

Isn't that 13-14 volts with the alternator hooked up?

I checked my voltage the other day, and from what I could tell on my analog multimeter, it looked like I was getting about 12.5 volts w/ the car off, and down around 12 volts when the car was running.... I had both multimeter leads directly on the battery terminals both times (not on a body ground or anything).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">Isn't that 13-14 volts with the alternator hooked up?
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Yea, I was saying it'd be easier to check your alternator that way vs pulling harness and lead off. If your voltage goes down with the car running, your alternators probably ****. Mine reads about 13.5 volts with the car running.

Pull your negative battery cable off with the car running, then you'll get an accurate depiction of what the alternator is actually putting out.

 

I read on Alternator Starter Express (where I ordered my alternator) that doing that could damage the electrical system.