Brake and alternator warning lights

[Hodaka]

I have a 1990 Pintara sedan and recently the brake and alternator warning lights have been coming on for no apparent reason.

Both lights always come on together and remain on for a few seconds or perhaps a minute.

There appears to be no fault with either the brakes or alternator.

The instrument cluster was removed and checked by an instrument technician who said each light was on a separate circuit and both circuits were ok.

Can anyone out there suggest a possible cause or where to look for one?

[rathies]

I believe that does mean your alternator is on its way out. If you want to find out, start the car and pull off one of the battery terminals. Hit it around the block and see if it cuts out.

[oldn_tired]

Yep sounds like alternator trouble, it could be and (excuse me as I'm having a VB block out) the resistor I think on the back of the alternator.
Any way it is held in by two screws and when removed has two sprung carbon contacts which go into the alternator.I
If these look extremely worn the unit can be replaced or you may like to try and get a better one from the wrecker first as they are not cheap to see if it fixes the problem.
If the contacts look ridged or grooved or you can put a finger in the alternator and feel where they are meant to make contact and it feels ridged then the alternator is basically stuffed  and if you replace the block it will just chew it out.
Wait is that another VB calling ,    why yes i think it is.

[ffourc]

the main wire from the alternator to the battery is known to corrode.check it, much cheaper to replace than the alternator.

start the car and pull off one of the battery terminals

DON"T recommend this

use a voltmeter (as low as $5 in cheap as chips) and measure the voltage at the + terminal (car running) should be 14.7 v (i think) at least more than 13 less than 15

that'll tell you if aternater is supplying.

[Virus]

the regulator's brushes are probably fuked or the regulator is fuked. Not sure on prices for them but iirc around $40.

Oh and i guess you drive a ca20 powered car? Cause those lights are what came on in my car when the regulator shat itself. Although mine was caused by heat due to the extractors but if you have the normal headers it will most likely be the brushes are warn out.

[oldn_tired]

yep thats it the regulator,(now have VB haze not block out)
I replaced one six months ago 40 bucks sounds cheap I thought it was more like 80
It was one of those things that for the price of the thing it made me go SHIT.
It is a generic part on a lot of alternators though and for a stroll through the wrecker with a screw driver I found a replacement in good nic for $2

[borgtj]

With all accesories on,you should be in the range of 13.8 volts or better,My stanza had the brake lamp and and alt come on and as you folks say,my altenator is stuffed.replaced it with a Maxima one modded to fit.

[rathies]

a weak battery can also lead to low voltages which is what i'm suffering from at the moment. Thats why i'd suggest removing it while the car is running, just make sure its the negative so it doesn't matter if it touches the side of the car.

[dave-trx]

a weak battery can also lead to low voltages which is what i'm suffering from at the moment. Thats why i'd suggest removing it while the car is running, just make sure its the negative so it doesn't matter if it touches the side of the car.

It is possible to damage the ECM by doing this.

[borgtj]

It is possible to damage the ECM by doing this.

One big voltage spike is all it takes,then [swearing filters own me]! you just let the smoke out of the ECM.

[Hodaka]

Thanks to everyone for your help. 

Reconditioning  prices ranged from $145- $250 and replacement alternators (new) $180 - $700!

After looking at the workshop manual I decided to track down a new regulator / brush assembly which cost $42 (Burson's Auto Parts Qld) and took 15 minutes to fit and it seems to have fixed the problem.

The old brushes looked ok but one measured slightly than the length specified in the manual.

[Virus]

probably cooked from the headers. My brushs were fine but my extractors cooked mine so i got a brand new replacement and made a heatshield outta a coke can No problems since. Not longer gets too hot to touch

[Barnett]

this happed to my old corsair! one of the plugs on the back of the alternator was damamged by the heat and was starting to fall apart and it was making the lights come on and then they would go away and then come back.....got it fixed by a auto sparky for $35 was fine for as long as i had the car after that....

[Barnett]