Jump to content
Ultimate Subaru Message Board

94 Legacy ABS,Brake,Battery lights all on


Recommended Posts

When I first start my 94 Legacy Wagon the ABS, Brake, & Battery sensors are lit up on the dash. They are on all at once and it only happens on the first start of the day. They disappear after a couple minutes. Just had a new alternator and battery installed. Any suggestions? Thanks!

Link to comment
Share on other sites

I believe these lights are in the alternator field circuit and will turn on if the alternator has a charging problem. I would have the people that worked on it look things over. You may need another one since it should not work like that. The charging should happen immediately after starting with no delay.

Link to comment
Share on other sites

  • 3 years later...

Wow. Glad there is such a wonderful forum to find answers.

 

I am having the brake light and battery light issue. My wife was freaking out and of course I am trying to explain to her that the car is not about to die.

 

What is the mechanics behind the brake lights coming on with an alternator problem- battery is obvious- but brake lights???

 

Glenn

Link to comment
Share on other sites

It means that the car is undercharging or the altenator is shot.

 

you need to have the charging system and the battery load tested. Yes it can mean the car can die if demand outpaces the output of the alt.

 

 

nipper

Link to comment
Share on other sites

Wow. Glad there is such a wonderful forum to find answers.

 

I am having the brake light and battery light issue. My wife was freaking out and of course I am trying to explain to her that the car is not about to die.

 

What is the mechanics behind the brake lights coming on with an alternator problem- battery is obvious- but brake lights???

 

Glenn

 

The lights are used in the field circuit for the alternator besides their normal function. So when the alternator has a problem those lights will light up also. It also gives a way of testing the warning circuits when the engine isn't running and the ignition is on.

Link to comment
Share on other sites

Yes don't wait on getting it checked out. The vehicle might work for a couple days without charging by the alternator depending on battery condition, load, etc., but if the alt is not putting out the car will stall out at some point.

 

The mechanics of the field circuit is here: EndWrench Erratic Warning Light Operation

When diagnosing a vehicle with erratic operation (flashing, dim illumination, etc.) of the handbrake/brake fluid warning lights, check the charging system and the charge light system. The charge light system (which receives a ground through the alternator field when the alternator is not charging) is used to check the bulbs of the handbrake/brake fluid warning lights (and some other warning lights on select vehicles).

Link to comment
Share on other sites

  • 3 months later...

Old post, I know, but didn't want to start a new one, so...

 

Just had the batt and brake lights come on this morning. Ordered a new alt from subarugenuineparts, will get here tomorrow.

 

In the mean time, what should I do? I'm sure I can make it home no problems, but should I hook up a batt charger overnight? I'm going to end up taking the car to get a new battery once I have the new alt.

Also, I've never messed with an alternator before, anything I should know before attempting an alternator swap?

 

Thanks in advance for any and all advice.

 

eag

Link to comment
Share on other sites

In the mean time, what should I do? I'm sure I can make it home no problems, but should I hook up a batt charger overnight? I'm going to end up taking the car to get a new battery once I have the new alt.

Also, I've never messed with an alternator before, anything I should know before attempting an alternator swap?

 

Thanks in advance for any and all advice.

 

eag

Put a 1 or 2 amp charge rate on overnight and make sure it has a full charge when you put in the new alt. Your battery should be okay unless it's really old.

 

I've never replaced an alt on a new gen so not sure about the tensioner. Should be an easy swap though.

Link to comment
Share on other sites

Put a 1 or 2 amp charge rate on overnight and make sure it has a full charge when you put in the new alt. Your battery should be okay unless it's really old.

 

I've never replaced an alt on a new gen so not sure about the tensioner. Should be an easy swap though.

 

And carry jumper cables, a good set, not the 9,99 set.

 

nipper

Link to comment
Share on other sites

Disconnect the negative terminal on the battery before you attempt to remove the alternator.

 

Also pay attention to the amount of play in the drive belt before you loosen it. That will give you an idea of how tight to make it on the install. You don't want to overtighten it.

 

Oh yeah... don't forget to reconnect the battery afterwards!:lol:

Link to comment
Share on other sites

So it's a fairly straight forward swap? Sounds like the only difficult part is getting the belt off and putting it back on at the proper tension. Any tricks to help that part?

 

I've been carrying jumper cables around since I was 16, thankfully my dad had a good concept of vehicular necessity. I can't even count how many times they've been used.

 

Thanks again

Link to comment
Share on other sites

Good call on going OEM reman alt vs parts store. Yes slow charge battery overnight so it is completely charged when you leave. If you don't run the headlights, heater, a/c, defrost, etc., you can get a few hours runtime if you have a good batt.

 

Yes definitely unhook a battery cable before starting work; the large gauge wires to the alt are always hot.

 

tension1.jpg

 

Not sure if it is the same for your vehicle, but here is belt tension for '00obw:

belt-tension-00obw.gif

Link to comment
Share on other sites

So, after I leave the car connected to the charger at 2 amps overnight...

I unhook the negative terminal to the batt, disconnect all wiring to the alt, loosen the lock bolt, relieve some tension by loosening the tension adjust bolt, remove the belt, unbolt the alt, and then reverse for the install, correct?

 

As far as belt tension goes, I'm assuming the specs are for total play? Meaning on a new belt, the tension would be such that the belt could move ~4mm up and ~4mm down?

 

Excellent help so far, by the way, my confidence is growing by the post. I appreciate the photo and diagram also. Beautiful work.

Link to comment
Share on other sites

Swap complete. I reused the belt becuase I remembered it was replaced at the same time as my timing belt.

Truely a simple swap, the hardest part was feeding the pivot bolt back through the holes.

 

Hopefully the lights stay off, I turned on all my accessories and drove around for 15-20 mins, car seemed to be a bit happier with the new alt.

 

Thanks again for the tips.

 

 

eag

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...