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Discussion Starter · #1 · (Edited)
My wife has an 88 Toyota Corolla (4af, I think) and the brake and battey light came on at the same time. Her car was on and all of a sudden, all the accessories wanted to turn off.
We turned the car off, and it would not start again. I assumed the problem was the alt. since it has never been changed, so I replaced it with a new one. The car has started up fine ever since,.. but the brake and batt. light are still on. The brake res. is full just above the max line.
Should I change the battery??? When I used a voltmeter,.. it read 13v's while off,.. and 14v's while on. I turned the headlights on and the volts dipped and went back up fine.
Is the battery suppose to measure 13 volts while off?? I thought it was suppose to measure 12v's???
Could this be the problem???
 

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Discussion Starter · #3 ·
homeguard said:
whats it do when you try to start it?
edit: try jumping it first also.
I replaced the alt. and it started fine. It has started fine for the past week and a half. The alt is charging the battery fine also.
The car cranks and starts right up,... but the brake and battery warning lights are still on.
Now her radio wont' start,.. I'm thinking there's a short somewhere but I cant find it. Why would both warning lights come on at the same time???
Any suggestions????:confused:
 

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Paseo
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The alternator may still be bad, might be working, but not in a proper manner. Also check the regulator.
 

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My brake light wouldn't go off. Check your brake fluid level first. My front pads were fine, but I needed new drums in the rear so check it out.
 

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i think the only sensor with the break light is on the hand break im not sure though, i am gussing this is a sedan?
 

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Discussion Starter · #8 ·
homeguard said:
you check all the fuses?
Yes.
But one fuse is bad,...it's the one under the hood that says "CDS".
it's one of those big peach colored fuses.
I replaced it,.. but the lightdidn't go off.
 

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Discussion Starter · #9 ·
SR5 Rolla said:
My brake light wouldn't go off. Check your brake fluid level first. My front pads were fine, but I needed new drums in the rear so check it out.
Brake fluid is topped off.
I have to check the brakes themselves.
The reason I didn't,.. is cause the charging light is on also.
 

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Discussion Starter · #10 ·
homeguard said:
i think the only sensor with the break light is on the hand break im not sure though, i am gussing this is a sedan?
How can I tell if is't the parking brake???
Both lights get brighter when I apply the p brake.
Could this mean something??
 

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The Return of the Red Coupe
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If the break light AND the battery light come on at the same time, chances are its your alternator, I learned that recently from experience. The alternator charges about half the time and the other half it will give low charge, this is why the brake/battery light comes on, it indicates that your alternator is producing a low charge (under 12V) and eventually it will stop charging.

If the brake light alone comes on, that means that your brake fluid is low, not that your brakes are broken or anything like that.. the only sensor is located on the brake fluid bottle and that's it, there's no sensor for worn out pads/shoes(well except for the squealing spring on brake pads) or broken parking brake cables.. you get my drift? :)
However there is a sensor on the brake lever that turns on when you put your parking brake on, this explains why your brake light gets brighter.
 

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Discussion Starter · #12 ·
REN69 said:
If the break light AND the battery light come on at the same time, chances are its your alternator, I learned that recently from experience. The alternator charges about half the time and the other half it will give low charge, this is why the brake/battery light comes on, it indicates that your alternator is producing a low charge (under 12V) and eventually it will stop charging.

If the brake light alone comes on, that means that your brake fluid is low, not that your brakes are broken or anything like that.. the only sensor is located on the brake fluid bottle and that's it, there's no sensor for worn out pads/shoes(well except for the squealing spring on brake pads) or broken parking brake cables.. you get my drift? :)
However there is a sensor on the brake lever that turns on when you put your parking brake on, this explains why your brake light gets brighter.
Well,..thats why I changed the alt. first.
But both warning lights are still on.
The new alt is charging fine. I've checked the battery once a day for the past two weeks and it measures the same volts (13v's).
I checked the battery and it's in good condition.
What else could it be??
 

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The Return of the Red Coupe
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hmmm.. bad ground maybe. maybe even a bad fuse. :confused:

and yes.. my alternator did charge fine.. but only half the time.
 

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Discussion Starter · #14 ·
REN69 said:
hmmm.. bad ground maybe. maybe even a bad fuse. :confused:

and yes.. my alternator did charge fine.. but only half the time.
I checked all the fuse before changing the alt.
How can I tell if I have a bad ground???
 

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I had that problem with my 4af also if you changed the battery and the alternator and the light didn't go away, also check the battery terminals if that still doesn't fix it then it this. its the main power wire on the postive side this same wire controls the choke on the car i think its a yellow wire, that wire is corrode or starting to break down over all the years and weather conditions like mine did so what you need to do is jump the wire from the alternator to the main power wire on the battery that way there two way for the power to get through the system. it took me 6 months to figure out the problem. it costed me 2 battery and alternator, over time is will overcharge the battery and burn the inside of the alternator. this should fix your problem like me know the outcome.
 

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Discussion Starter · #16 ·
CanadaGTS said:
I had that problem with my 4af also if you changed the battery and the alternator and the light didn't go away, also check the battery terminals if that still doesn't fix it then it this. its the main power wire on the postive side this same wire controls the choke on the car i think its a yellow wire, that wire is corrode or starting to break down over all the years and weather conditions like mine did so what you need to do is jump the wire from the alternator to the main power wire on the battery that way there two way for the power to get through the system. it took me 6 months to figure out the problem. it costed me 2 battery and alternator, over time is will overcharge the battery and burn the inside of the alternator. this should fix your problem like me know the outcome.
Not sure which wire you're talking about,.. but I cleaned out my terminals already so i doubt thats the problem.
I'll try the wire solution, but I dont know what wire.
 

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ok tommorrow i'll get the exact wire colour and hopefully i can find the wire diagram for the 4af engine. It not your alt or battery on the 4af just the battery light wil come on. for 4ag both those light come on. now i'm like 90% sure that it the same problem i had with my 4af. i'll post if by 10pm wednesday night
 

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ok i found it, unplug your alternator there should be three wires from plug a yellow , white and a black and yellow. teh problem is the yellow one cuz it runs to teh choke then to the battery, do you notice that sometimes the car's rpm is low, this wire cuz that problem also. anyways get a new wire a little thicker than the yellow one join that new wire to the yellow but don't cut off the old one you still need it so now the yellow wire splits into two run that new one all the way under the rad support till you get to the postive side of the battery which should have the yellow color and do the same to that wire. so now the power has to ways to get around. but cuting the old wire it messup the choke from the wire diagram the wire passes on both side of it. it a big job to try and renew this wire at that point might as well do and engine swap. anyways that should fix the problem. let me know the out come. oh also when you do all that disconnect the negative also and put back like it was a new battery. why i'm not sure when i did just the postive the light stayed on. when i did both teh light never came back, or it just could be my car.
 

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Discussion Starter · #20 ·
CanadaGTS said:
ok i found it, unplug your alternator there should be three wires from plug a yellow , white and a black and yellow. teh problem is the yellow one cuz it runs to teh choke then to the battery, do you notice that sometimes the car's rpm is low, this wire cuz that problem also. anyways get a new wire a little thicker than the yellow one join that new wire to the yellow but don't cut off the old one you still need it so now the yellow wire splits into two run that new one all the way under the rad support till you get to the postive side of the battery which should have the yellow color and do the same to that wire. so now the power has to ways to get around. but cuting the old wire it messup the choke from the wire diagram the wire passes on both side of it. it a big job to try and renew this wire at that point might as well do and engine swap. anyways that should fix the problem. let me know the out come. oh also when you do all that disconnect the negative also and put back like it was a new battery. why i'm not sure when i did just the postive the light stayed on. when i did both teh light never came back, or it just could be my car.
Thanks for your help. I'm gonna try that this week.
I'll post back and see if it helped.
 
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