battery + brake light problem... Alternator tested fine!

[0ptimus prime]

Alright so i've searched a butt load about the battery + brake light problem. I narrowed it down to my alternator being dead.

I took the alternator to auto zone, and they tested it. Now here's the kicker, it tested fine! So i bought new battery connectors (mine were barely hanging on) and put them on. Still the battery and brake light come on. I'm running out of ideas here because the alternator no longer seems to be the problem?

[The Mic]

I'm not sure about the battery light, a failing serpentine belt can cause the light to go on. Have it checked out.

For the brake light (I'm assuming you're talking about the one in the dashbaord) there could be a couple of things things wrong. Either you're low on brake fluid or you might have a brake tailight that's out. If those are fine tell us so we can narrow this down.

[PoorManQ45]

Brake light on dash = low fluid or failed ABS(if you have it).

Battery light problem might be a failed sensors.

[yellow_jacket]

Brake light on dash = low fluid or failed ABS(if you have it).

Battery light problem might be a failed sensors.

You either have two different problems as stated above, or you have an open circuit condition in your wiring. Get a multimeter and check continuity in the charging circuit. Also check and seen how many volts you've got with everything off, and with everything on(lights, wipers, a/c, turn signals etc etc) You will need to bring the rpms up a little for the the full load test. You should be running around 14.5 volts. If you are running anywhere near 12.5, then you know you are looking at a wiring problem. If you would like, post the results and we can help you further.

[0ptimus prime]

ok i just swapped out my sr20 alternator with a modified KA alternator. The car ran fine for a while (the brake and battery light went off) so i thought it was fine. Low and behold, it died again in the middle of nowhere

Now i'm screwed because i don't know what it can be. We tested the battery with the car off (12 volts) and tested it with the car on (dropped to 11.8 volts.) Then, with all the lights on, it dropped to 11.0 volts.

I know it seems like the alternator isn't working, but i'm sure that alternator was working on my KA. Could there be a ground or a wire that could be causing this? I checked the fusible link and that's fine too.

[bdrifta]

This is pretty crazy...i seem to be having the same problem...for some reason if i turn on my headlights my boost controller turns off. Its like there isn't enuf current to power everything...also note. Brand new gell cell battery, and brand new ka24de alternator of which tested 95 amps.

[PoorManQ45]

Alternator is NOT working.

Check the connection from the alternator to the battery, and the main grounds

[spider_slayer]

check your belt too man. make sure it hasn't loosened up or anything.

[yellow_jacket]

Alternator is NOT working.

Check the connection from the alternator to the battery, and the main grounds

Like he said, the alternator will not work if the wiring to it is bad. It must see the system voltage in order to correctly function. Check the wiring. I believe there is even a fsm floating around here somewhere.

[travisn]

when something electrical stops working check a FUSE there is one in the engine bay by the air filter that has the alternator fuse, check that fuse

[travisn]

oh, about the brakes... take off the center console and check the switch on your ebrake, it might be in the closed position when the ebrake is really all the way down... and check brake fluid... hey the lights there for a reason, maybe you have a leak...

[srdrps13]

that seems like the same problem as mine... my alternator had a bad ground and killed my battery i fixed the alternator problem then got a new battery. could be something different tho idk. this fixed my problem

[mikesloud]

I had the same damn trouble, checked all wiring etc, alternator. check your ecm control fuse under hood. it is blown ,replace it that will fix it. after all that work it something so simple.

[nothingFancy]

my battery and brake light is on aswell. but heres the kicker to mine. they shut off at idle and come on when im driving. but they shut off when i have it floored at 4k rpm to redline.

what can that be??

[jt15833]

if battery and brake light are on and your not charging the issue is your charging system. check to make the the fat wire that bolts to the alternator (not ground, its fat should be black/red) also bolts into the fuse link/relay box under the hood. check that its grounded.

[crookedcop7]

I had the same problem to fix the light problem remove the bulb check relay that will get the rid of the lights BUT.... it will still drain your battery I finally got fed up with it and took it to a shop now im waiting to see if they can fix it

[nothingFancy]

well i found out why i had my problem, the alternator was over charging my battery so i replaced it and runs good