1991 Toyota Corolla DX BRAKE and BATTERY light on at same time. - Toyota Nation Forum : Toyota Car and Truck Forums

tornado542 · 03-30-2010, 07:33 PM

Hey guys,

My 1991 toyota corolla DX brake and battery light is coming on intermittenly as i drive. What does this mean?

Thanks

Alex

Murgatroy · 03-30-2010, 08:25 PM

Do they both come on at the exact same time and go off at the exact same time?

If it is the brake light at some times and the battery light at others they are probably not related.

Check your brake fluid and make sure your ebrake handle is down. A lot of folks don't realize that the brake light will come on when the fluid is low. That means if you brake hard, accelerate hard or corner hard, the fluid can intermittently drop below full, causing the light to illuminate.

As for the battery light, what revs does it happen at? Is it predictable or does it happen at random times. Sometimes while cruising, sometimes at idle? If you park the car and hold the idle at a steady 2500 RPMs, does it come on? If so, your alternator is not charging and you should start your search there. Is the belt tight, are the battery cables clean and tight?

However, if everything is groovy (belts, fluids, etc...) and both lights illuminate at exactly the same time with no discernible cues as to why they are coming on under random conditions and stay lit the exact same amount of times; I would start searching the wiring, making sure all connections are tight. Start at the battery ground.

***SCT*** · 03-31-2010, 01:51 AM

YES, they ARE RELATED! When both the Brake and Battery light comes on. It's programmed to do so when the alternator is no longer good.

It's your alternator on its last leg. Get the alternator checked, more than likely it'll have to be replaced. Of course, taking into account that the belt is fine...

When these two lights come on at the same time, it basically means the car is running more off the battery than what the battery is being charged. Eventually, the car will die if you don't get it serviced soon enough. I was able to drive with them on for about 20 miles, that can greatly vary.

tornado542 · 04-01-2010, 12:44 PM

The BATTERY and BRAKE lights come on only when I am stopped at an intersection or idling. When I hit the gas, they go away. Is that an indicator of anything specific?

Murgatroy · 04-01-2010, 12:49 PM

Yes, your engine is not turning fast enough to get your alternator to charge.

Check your belt. If the belt is tight, take the car down to a parts store (Autozone, Advance, O'Reilly's, etc...) and have them test your alternator. It is most likely going bad.

***REN69*** · 04-01-2010, 07:24 PM

Wut? ^

I've never heard of an "engine not turning fast enough to get the alternator to charge"

if the belts are bad or not tight enough, they would squeal forever.

This question pops up every other day, I'm going to have to make a sticky eventually.

if only people would search for "brake and battery light on" the other hundreds of threads would pop up.

Donald · 04-01-2010, 07:40 PM

Quote:

Originally Posted by SCT

YES, they ARE RELATED! When both the Brake and Battery light comes on. It's programmed to do so when the alternator is no longer good.

It's your alternator on its last leg. Get the alternator checked, more than likely it'll have to be replaced. Of course, taking into account that the belt is fine...

Yep!!! Happened to me on a trip from Miami in my Camry. Car finally died near Orangeburg SC, on a Holiday, at night, on one of the most desolate stretch of I-95.
Yep, I got my moneys worth out of my AAA membership.

I wouldn't even have the alternator checked, beacuse it is intermittent, it might check good. Just replace it.

I have been told that the most common reasons for alternators to die is corroded or loose battery cable ends, and jump starting another car with your engine running.
Both those things can cause the internal diodes to fail. It might take a week, it might take two years.

The best way to jump start another car without risking your alternator is, connect the cables, with your engine off, try and start the other car.
If that won't do it, with the other car turned off, run your engine for about 5 - 10 minutes to a charge on the battery of the other car.
Turn your engine off, then try starting the other car again.

***SCT*** · 04-01-2010, 07:49 PM

Anything that draws a lot of power can kill it too, someone told me. Like sound systems with a sub, amp, etc. on blast (of course, a capacitor will alleviate the problem).

I was like 30 minutes away from home when it struck me. Car ran like a dog that had been shot in two legs. Turned the headlights off, car ran better! But I needed them, it was at night.

Sometimes it could mean an alternator is OVER charging the battery, which can kill the battery. Alternators can have more than one diode to control power and a faulty one can throw too much power out.

Donald · 04-01-2010, 08:04 PM

Quote:

Originally Posted by SCT

Anything that draws a lot of power can kill it too, someone told me. Like sound systems with a sub, amp, etc. on blast (of course, a capacitor will alleviate the problem).

I was like 30 minutes away from home when it struck me. Car ran like a dog that had been shot in two legs. Turned the headlights off, car ran better! But I needed them, it was at night.

Sometimes it could mean an alternator is OVER charging the battery, which can kill the battery. Alternators can have more than one diode to control power and a faulty one can throw too much power out.

I think it is more the current surges than just a power draw, but yes, it can over charge the battery, boil out all the acid and warp the plates too.

Murgatroy · 04-01-2010, 09:02 PM

Quote:

Originally Posted by REN69

Wut? ^

I've never heard of an "engine not turning fast enough to get the alternator to charge"

if the belts are bad or not tight enough, they would squeal forever.

This question pops up every other day, I'm going to have to make a sticky eventually.

if only people would search for "brake and battery light on" the other hundreds of threads would pop up.

At idle (700-800 RPM) the alternator is not turning fast enough to charge the battery. If the belt is loose (they don't always squeal) that means the alternator is turning even slower because the belt is jumping. An alternator doesn't start 'charging' the battery until 2000+ RPM, so at idle, if the alternator is not making any output, the battery is going to be draining, causing the battery light to come on.

That means if the alternator is on its way out, and it only charges when the engine is going 2000 RPM or more and the light comes on at idle, the engine isn't turning fast enough to get the alternator to charge. A good alternator will put out enough amperage at idle to run the system. But not to charge. Rev the engine and it turns the alternator faster, creating a charging state. The idiot light is meant to come on when the system is pulling more juice than is available from the alternator. Meaning it is draining the battery.

No, I wasn't just making it up.

I am sorry if I wasn't clear when I said that.

hastings900 · 06-17-2010, 06:56 PM

I have a 91 toy corolla over 300,000 miles on it. I had replaced the alternator because the brake light and alt light came on at the same time. For some reason the battery is not getting a change form the regulator. My problem and your problem are of the same. in the book I have it says that there are 3 wires that come from the back of the ALT (1) White that goes to the battery post (2) Black with yellow stripe, All it says is that Hot in run or start position (3) Yellow goes to the warning light on the dash and then runs into ignition switch. Now when I check for continuity it tells me that black with yellow stripe is grounded because the buzzer I have on my volt meter goes off when I apply my negative wire form the meter to the car and apply the positive side of the meter to the plug that the black with yellow wire is located. So I guess is there something I am missing or is the wiring messed up on this car.
Thanks

verlaryder · 06-19-2010, 02:31 AM

brake and charge light on intermittently or continuously nearly always means the alternator brushes are worn too short.
Toyota dealers sell new brushes and the brush holder for about $25.

hastings900 · 06-19-2010, 02:29 PM

Hello after all the problems trying to figure out why I wasnt getting change from the ALt to The battery. If you have a Battery and ALT light come on your can and you take the ALt in and have it checked and they say its good. Then check the terminal post connection on your ALT It may be bad. just cut it off and replace it with a copper cable lug 1/4 inch hole size. I bet that will fix the problem. So a recap if you dont have a charge from the alt and the alt is good after it is tested. Replace the post connector on the wire.

Thanks
Gary

toyotaboyfreak · 06-23-2010, 12:53 PM

Quote:

Originally Posted by SCT

YES, they ARE RELATED! When both the Brake and Battery light comes on. It's programmed to do so when the alternator is no longer good.

It's your alternator on its last leg. Get the alternator checked, more than likely it'll have to be replaced. Of course, taking into account that the belt is fine...

When these two lights come on at the same time, it basically means the car is running more off the battery than what the battery is being charged. Eventually, the car will die if you don't get it serviced soon enough. I was able to drive with them on for about 20 miles, that can greatly vary.

true! this just happened to me a month ago... alternator needs to go..

Donald · 06-23-2010, 02:36 PM

LOL!
I just changed the alternator in my sedan about a week ago. What is this, an epidemic or something?

I had washed the engine, and the next day both lights came on.
The alternator was covered in crud from a blown CV boot that slung stuff all over the right side of the engine bay. I think some of the crud got inside and did the deed!