I have an electrical gremlin

[grampi]

My '99 Corolla just started having an electrical problem. On my way home Friday night (I have a 5 hour drive from IL to OH on the weekends) I was listening to my audio system as I usually do. All of a sudden I noticed my Alpine head unit going through its power-off sequence (just the same as it does if I push the power button to turn it off) and then it turned off for a few seconds and then came back on, all on it's own. This happened about an hour into my drive. Then a couple hours later after it was dark, more things started to happen. Normally when I'm driving at night, I can see my headlights dimming if I really push the volume on my system as the amp I'm running can pull some pretty good current when the subs are hitting a bit harder. The dimming has never been severe, so I never really worried about it much. Now I'm listening to the system at a fairly low volume, the subs are barely playing, and my headlights are dimming so badly it looks like they are flashing on and off. Then just after this occures, the head unit shuts down again, then comes back on. Then I noticed if I tap my brakes, the headlights go completely out for a split second then come back on. My amp is connected directly to the battery and is fused right next to the battery. The head unit is connected to the fuse box and it too has a fuse in its power lead. I'm assuming neither power lead is shorting as that would cause their fuse to blow. I'm also not getting the relationship between the head unit turning itself off, and the brake lights momentarily killing the headlights. It almost acts like there's a weakness in the electrical system somewhere rather than a short. I wonder if the battery or the alternator is going bad? I would lean towards a bad battery as I would think a problem with the alternator would generate a check engine light, and there may also be another idiot light that would indicate an alternator problem. Plus I believe the battery is at least 5 years old. However, the battery always starts the engine without problems, and doesn't seem to struggle doing so. My symptoms are very strange and because of this I really don't have a clue what to look at for a remedy. What do you think?

 

[hate2work]

Wow, that's one long paragraph lol

The first thing I would do is replace that battery. It's 5 years old so it's due anyway. No sense in trying to chase a problem that's not there if it's just your battery.

 

[scurvy]

Sounds like your alternator is toast and your battery was mightily weakened.

What's the voltage at the battery terminals with the engine off, when cranking and at fast idle?

 

[eljefino]

Pull the fuse for your head unit so it's just the car's stock wiring. Run the engine and confirm with a digital voltmeter you have ate least 13.8 volts at the battery terminals. (Mid 14s are common and better.)

Not all alternator failures result in an idiot light.

Then before anyone else says it, check your battery terminals and grounds. Eyeballs don't cut it-- take them off and look inside.

 

[40Deluxe]

Take stereo and sub out of the electrical loop , then clean battery terminals,if problem persists then have alternator checked and battery load tested.

 

[Dan55]

+1 isolate the stereo from the system . I had a car audio system years ago with intermittent sound .In the end it was the wiring over time that was pinched and and shorted.

 

[grampi]

Lots of good advice. I'll check this stuff today and report back with what I find. Thanks.

 

[94MaxGXE]

I think you have a bad/corroded connection in the high current circuit of the battery. This could be the positive side or the negative side. Clean the battery connections.
I would take a close look at the battery cable connections, especially the battery negative cable where it connects to the engine. Clean the negative battery cable where it connects to the engine.

Being that the stater seems to work OK, the battery to engine connection are probably OK. That would point me more towards the engine to body ground circuits.

The ground straps from the engine to the body are an important part of this circuit.
On my 99 Camry, there were at least three or four heavy black ground straps wires that went from the engine to the body. Each one had a quick disconnect spade type connector in the middle of the wire. Make sure those are not all corroded up. Remove the ends at the engine and body and clean them up.

 

[Jimmy9190]

If the headlights are dimming, even just a little it means you are drawing too much current when the system is on. It sounds like your battery is bad, probably due to drawing too much current from it with trying to power the stereo system and run the car at the same time.

First thing to do is disconnect the amplifier's power wire at the battery. Don't worry about disconnecting the radio, the car is designed to be able to power a radio. Remove the positive and negative terminals from the battery and clean them up nice and shiny with a battery terminal tool. It would be good to also check and clean the negative cables that should be grounded from the battery to the engine block somewhere. Check and clean your positive cable connections at the power distribution center (if you have one under the hood) and at the back of the alternator. If the alternator has a separate ground wire, check and clean the connections there too, both at the alternator and at the point where it is grounded. If the alternator grounds through its case to the engine block, use a wire brush and clean the mounting/ground locations.

Re-connect the battery and check the battery voltage with the car off, you should have at least 12.5 volts across the terminals. Start the car and check the voltage with the car running and no accessories on at all. You should have 13.5 to 14.5 volts across the battery terminals. Then turn on the AC on high speed and turn on the high-beam headlights on. You should see no drop in voltage at the battery. If the voltage does drop, there is a possibility the alternator is weak or defective.

Also check to be sure the amplifier is grounded to clean bare metal, preferably with a bolt that goes into the frame of the car. Seat belt bolts make excellent grounds for high current amplifiers.

You can take the car to Autozone or Advance, they can do a load test on the battery and their meter also tests alternator output, but I really don't know how reliable the alternator part of the test could be. If your battery fails any of these tests, replace it first. Your alternator could be in weakened state from the strain placed on it from the audio system and trying to support a failing battery. If you replace the alternator, maybe see if the parts store can get you one with a higher amperage of output. If not, maybe check with a local high-end independent car audio shop. There are companies that make higher output alternators for car audio systems but they can get expensive.

You probably do have a bad battery. After you replace it you should add a stiffening capacitor to your audio system. It will stop the dimming headlights and take some of the strain off of your electrical system. The stock electrical system on a Corolla is not that strong to begin with. You can buy a stiffening cap at any good car stereo store, Ebay, Crutchfield. etc. Probably a 1-Farad cap like this one would do fine for you, if all you have is the one amp in your system:

http://www.crutchfield.com/p_211ZN11FC/StreetWires-ZeroNoise1-Capacitor.html?search=capacitor

Adding a capacitor is cheaper than buying a new alternator. It's also cheaper than adding a second battery to the system. If you still have problems after replacing the battery and adding the capacitor, you may want to get your amplifier bench tested. It could have problems with its power supply, causing it to draw too much current now. This could especially be true if you have had the amp for a while, it was OK to begin with but has been played at high volume levels a lot of the time.

One last thing to consider is your own hearing. I don't mean to sound like your mother but if you are playing the system at high volume levels like that you will damage your hearing. I damaged my own hearing from many years of installing loud car audio systems, having my own very loud car systems and going to a lot of very loud concerts. I have tinnitis and I don't hear as well as I should now. Play it loud if you want, but wear ear plugs. Later in your life you will be glad you did.

 

[SteveSRT8]

I disagree that the battery is bad simply because the lights are dimming. The car doesn't run on the battery, it's just for starting and the alternator should pick up the slack.

of course the battery could still be bad, but I like the Cap suggestion. This really helps if you have a big amp that wants a huge surge for a subwoofer.

The ground(s) are suspect on almost any vehicle. Consider adding some new ones after you've checked out this problem.

 

[Kestas]

I had a similar episode during one trip. Pretty scary, I didn't know if I'd make it home. It turned out to be a loose battery cable.

 

[Rick in PA]

With all the talk about EVs, when I read the title to your post, my mind briefly flirted with the thought of a battery powered 1970 something AMC Gremlin....

 

[grampi]

The weather's screwin me. My garage is so full of junk I can't work on the vehicle in there, so I have to rely on the weather to cooperate, and it's not. It was cold and rainy yesterday, and it's supposed to be that way all day today too. I have to leave tomorrow to go back to IL (where I work) and I won't get another chance to work on the car until I come back home in 2 weeks. I'll just have to leave the stereo turned off and hope the car makes it for another 2 weeks.

 

[eljefino]

There's a saying in medicine, "if you don't take the time to be well, you'll have to take time to be sick."

At the least pull the fuse for your amp. It could be drawing current even powered off if its sensor relay is pooched or something.

And bring tools and jumper cables.

 

[grampi]

Originally Posted By: eljefino
There's a saying in medicine, "if you don't take the time to be well, you'll have to take time to be sick."

At the least pull the fuse for your amp. It could be drawing current even powered off if its sensor relay is pooched or something.

And bring tools and jumper cables.


There's nothing wrong with the amp's relay and it can't come on unless I turn the head unit on, which I'm not going to do. I do have a tool kit and jumper cables in the car in case of emergency. Luckily I also have an XM satellite radio in the vehicle I can plug a set of headphones into or I'd go nuts!

 

[Jimmy9190]

Even with the radio off and the amp not turned on, the power supply in the amplifier is still drawing power. With a questionable electrical system (battery, alternator, cables, etc or a combination of either) it is a very good idea to disconnect the amp's power wire at the battery until you can find the problem and fix it. This is especially a good idea considering you have to make a long trip in cold weather before you can fix the problem.

If possible, even if done on your way out of town it would be good to stop by Autozone or Advance and have them test the battery and alternator. If you do have a bad battery, Autozone will install a new one for free. Then the Autozone guy will be the one out in the freezing rain, not you. Or you could find some type of shelter like a drive through lane at a bank (they are closed today for the Presidents Day holiday), a gas station awning, or some other shelter to keep the rain off of you and your car and replace the battery yourself. It's not that much work and doesn't take many tools to swap out the battery on your car.

It's just my opinion but I would advise against taking a 5 hour trip in freezing weather with a battery that may or may not be in good enough shape to get you there without problems. And even with a new battery (assuming the battery is the problem) you should still leave the amp disconnected from the battery until you are able to be sure the alternator, cables and all cable connections and grounds are OK. Blinking headlights when the bass hits a good lick is not a good thing. It means the amplifier/sound system is causing undue strain on your electrical system. The stiffening cap will help and probably eliminate it, but I would advise against using the amp again until you add a cap to the system and get the car's electrical system repaired.

Just my 2 cents.

 

[grampi]

Not trying to be a wise guy or anything, but I don't see how the amp's power supply can be drawing power if the amp is turned off.

 

[brianl703]

Originally Posted By: grampi
Not trying to be a wise guy or anything, but I don't see how the amp's power supply can be drawing power if the amp is turned off.


A faulty amp may not turn off and continue to draw power. It's connected to constant 12V and draws power through that connection. The switched 12V or "remote" connection is only there to signal the amp to turn off or on. It draws very little power through this connection.

 

[grampi]

Originally Posted By: brianl703
Originally Posted By: grampi
Not trying to be a wise guy or anything, but I don't see how the amp's power supply can be drawing power if the amp is turned off.


A faulty amp may not turn off and continue to draw power. It's connected to constant 12V and draws power through that connection. The switched 12V or "remote" connection is only there to signal the amp to turn off or on. It draws very little power through this connection.


The amp is not faulty and does not turn on unless the head unit is turned on. Therfore, I don't see how the amp can draw any current if it is not turned on.

 

[Jimmy9190]

At idle, with the stereo system turned off, the amplifier's power supply is connected to power and ground. It does draw some degree of power from the battery. In a normal situation, the amount of voltage it draws is pretty negligible, usually less than half an amp of current. At idle, amps nowadays probably draw .03 or less of current due to better construction and quality of parts.

Your amp may (or may not) have an internal problem that causes it to draw more current than it should when the system is on. If the amp does have power supply problems, it can and usually will draw more current than it should, whether the system is on or off. I have seen it happen, more times than I care to remember.

Disconnecting the amp from the battery is only a smart way to remove what may be a source of current draw from what may be a mariginal battery, a possible weakened alternator, or both. Or you could have a simple problem like a loose battery cable or a corroded ground conmnection.

It's much better to take the amp out of the circuit until you can identify the real cause of the electrical problem and fix it.