[6g72]

after I changed my dying alternator for a new one?
the alternator is working fine havent had a problem with it but the brake/battery light never turned off and I checked all the fuses and they all work.. kinda wierd.. anyone have an idea?

 

[briar17]

Have you tried disconnecting the battery to reset everything? Were they on to begin with or all the sudden? You've of course checked that you have ample brake fluid etc right?

 

[MarkSpyder]

my guess would be your serp belt is loose and not spinning the alt as fast as it should. A bad/weak output from the alt causes both of those lights to come on. If the belt is already tightened properly then try disconnecting and reconnecting the battery. If the lights still come one then have the "new" alternator checked.

 

[6g72]

the alternator is perfomring great.. when im running it rarely goes under 14 volts and the belts are tightened.. before the lights would only come on when the old alternator stoped producing a charge.. I could tell cuz i saw my voltage slowly start to drop.. suddenly the alternator would work again and the brake light/battery light would turn off again..

I then installed the new alternator and the lights stayed on for ever, car hasnt given me any problems tho..

 

[MotoaFreak195]

Wow, i had the same thing happening to me, except my ac/heat indactor kept turning red to green and goign back and forth....and car ran, but finnally everything electrical quit.

It turned out that the damper was just laying there and the belt fell completely off and couldnt charge the battery.

and this whole process lasted about 2 weeks...lol...jsut getting worse and freakier

 

[Bios24]

Not sure what the brake light has to do with the alternator. To my knowledge the brake light will only come on with the parking brake, or if the brake fluid is low. Check your brake fluid?

 

[MarkSpyder]

Not sure what the brake light has to do with the alternator. To my knowledge the brake light will only come on with the parking brake, or if the brake fluid is low. Check your brake fluid?

I had ordered an aftermarket high output alt awhile back. After having it professionaly installed I notied that the battery and brake light would come on at the same time (whenever I was under 3Krpm). As soon as I hit 3Krpm both lights would go off. The cr ran fine but headlight would be dim, bass was weak, etc. I replaced the alt with my OEM one and everything was fine again. I chalked that up to the alternator not putting out the proper CURRENT (not volts) for the ECU, thus triggering the lights. :dunno: My brakes (wheel and emergency) were perfectly fine. I've never had a problem with any of them.

 

[6g72]

I had ordered an aftermarket high output alt awhile back. After having it professionaly installed I notied that the battery and brake light would come on at the same time (whenever I was under 3Krpm). As soon as I hit 3Krpm both lights would go off. The cr ran fine but headlight would be dim, bass was weak, etc. I replaced the alt with my OEM one and everything was fine again. I chalked that up to the alternator not putting out the proper CURRENT (not volts) for the ECU, thus triggering the lights. :dunno: My brakes (wheel and emergency) were perfectly fine. I've never had a problem with any of them.

yea thats what would happen to me with my old alternator.. as soon as it started giving low voltage the lights would come on.. then they would turn off when the alternator was working again..

changed the alternator for a new one and it just stayed on for ever weird

 

[CHRIS7891011]

I actually had this same problem. Turns out I had a couple blown fuses (seriously!). I changed those and things went back to normal.

 

[BlackEclipse]

With my old Galant Brake and battery light came one when my alternator was bad

 

[blueeclipsegt]

I have the exact same problem. Does anybody know for sure the solution? Like he said, below 3k the brake and volt would turn on. I have had the oem alternatro replaced and then the new one was replaced right after. I thought it had to do with the aftermarket hid kit so I yanked them out (after the second replacement was in). Everything was fine but those lights turned on. My starter seized up a wk later and wound up killing my yellow top Optima. So including the professionally installed alternators, new batery and starter, I am up to 600+. I will have the belts checked as well as the alternator to ensure that it is it. I sure hope its not as major as an ECU prob. SOMETHING TO NOTE: No codes are being sent out, so it isnt a sensor I believe. Please can someone send me a direct response on here. Thank you in advance, Derrick

 

[MarkSpyder]

Sounds like you had a bad alt and/or the serpentine/accesorries belt was slipping or not tight enough.

 

[shcernsise]

My lights came on when my serp belt came loose. I tightened them back up and they went away.

Are you 100 percent sure that you have the correct alt on your car! It may be a little bit different, or if it is a refurbished model like many are - they just replace the windings inside - it could still be screwy

There are many alts that can fit on any car. For example the shop put a wrong alt on my brothers 99 GST and it was functioning fine - or so we thought. The battery ended up blowing up. It may be giving out the same current, ect but it can still be the wrong one for our cars.

Thats why I asked if you are 100 percent sure about having the correct one on there - not because of the current being fine.

 

[DaBigKid]

i know this is an old thread but for those that dont know the charging light(looks like a battery) and brake light are connected through a one way diode, if the charging system has a problem both lights will come on. if its just brake fluid or something in the brakes then just the brake ligh will come on. Notice in a normal operating car if your e-brake is on the brake light is on and not both charging light and brake light...just a little fyi

 

[CujoJpN]

Thanks for the info guys.
Although mine is different (i think). I was cruising down the highway and then both just popped on. I have no clue why. I checked fuses and everything was good. I checked to see if the belt was loose or missing. And I don't think it is an alternator since the car remains running under low idle and doesn't stutter or even act like its going to kill. The volt/brake lights remain on even at high RPM's. I mean I could be at 5500RPMs and the lights remain well lit. They are never dim. So I am leaning away from the alternator theory.

But what else could it be?

 

[CujoJpN]

Anyone have any idea?

 

[CujoJpN]

Alright, in case anyone cares (which i doubt). i went and scanned my car with the OBDII scanner. And apparently when the brake light and the voltage light are on its catastrophic alternator failure. The code is P1500 (which isn't on the list of OBDII codes on the sticky), P1500 which is a "Generator FR Terminal Circuit Malfunction."
So apparently the alternator is sending unregulated voltage levels and has a good chance of destroying the ECU.

What I want to know is, how the fuck did it come to this?

 

[DaBigKid]

hhmmm that sounds really bad lol im actually having the same problem as you replaced my alt and fusible link and getting ready to do the bbelt hopefully im not in the same boat as you

 

[CujoJpN]

hhmmm that sounds really bad lol im actually having the same problem as you replaced my alt and fusible link and getting ready to do the bbelt hopefully im not in the same boat as you

So you replaced the alt and still are getting the same issue? Really odd. I am assuming that the P1500 means either =altenator failure, or multiple fuses being out. i just started up my car again and it is just all messed up. Drivers side windows fail to open or close, it doesnt even attempt, you cant hear the motor click. However lights dim when trying the window. passenger side window opens and closes VERY SLOWLY. This problem makes me wonder about the fuses. Also side mirrors dont move, they move with little to no power it seems.

It's a failure electronically.

 

[SpyderMan03]

I'm having a very similiar problem as mention in this thread.
I have a Check Engine light on. (has been for a while now actually.)

Everynow and then my battery light and brake light come one but go off shortly.
I borrowed a scanner and will check my codes this weekend.

I'm thinking I'm going to have to replace the all too.

I also have an Escort 8500 X50 and it's got a mode that will display the system voltage.
Well it fluctuates from 13 to below 10.
When it hits below 10 it sets of a "low voltage" alarm on the detector.