# Intermittent Battery and Brake light



## ConKBot of Doom (Jul 24, 2006)

This started thursday night, I started up my car, and the brake light(the one on the dash,not the tail lights... just to prevent any confusion) and the battery light are both on. I was at a friends house, and it was late, I figured that I had just lost an accessory belt, and I would just drive home on the battery while it lasted... But lo and behold once I got up to highway speeds, the lights turned off at the same time.

Today, the problem surfaced again, I was accelerating hard, and when I let of and shifted into 5th, as the RPMs dropped, the lights came on again, untill I got back into the gas. Now, it appears, that the lights kick on if I rev the engine up to >5k or so(clutch in...), and when it slows down to <4k, the lights turn on. They then stay on till I start accelerating under load.

I thought the brake light only came on when your parking brake was up, and when your master cylinder was low on brake fluid, which has me baffled, since my brake fluid is topped up all the way (it was full before I put the new pads on... so it got extra full ) 

I was thinking dying alternator, but the car idles fine without the lights, and the engine can be going 3k, and the lights can be on, so I dont expect it to be the alt. 


Cliffs: Brake light and battery light randomly lighting up and going out, together.

oh, and its a 94 sentra LE 1.6L 5spd, power steering, no ABS.

Any thoughts? thanks.


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## Brokeser (Dec 8, 2005)

You are correct in assuming the alty is at some fault. It's one of three things:

1. Loose or stretched alternator belt.

2. Check all the alternator connection, especially the ground wire.

3. The alternator has seen better days and is ready for retirement.

a. Take it to one of those auto part store that have the capability of checking that....

L


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## gekdis (Jun 25, 2006)

this exact thing happend to me a few months ago. It turned out to be the alternator.


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## ConKBot of Doom (Jul 24, 2006)

Yeah, looks like you guys are coming to the same conclusions I'm coming to... especially since tonight the stereo was being flaky, and when the stereo would cut out, the dash would dim. I'll replace the belt, and get the alternator tested, replacing it if needed.

The brake light was confusing me though. Thanks :thumbup:


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## ConKBot of Doom (Jul 24, 2006)

blah, I'm installing the new alternator and trying to put in new drive belts too, but the P/S and water pump belt is being a pain in the ass to loosen. I have the tensioner on the PS pump loose, but the pump isnt moving. I see one bolt on the back side of the pump holding it, I'm trying to loosen that... Is that the right bolt? Its a 14mm bolt, and I sheared my socket adaptor trying to loosen it, after I used PB blaster on it (to be fair it was a 3/8 >1/4" adaptor for my shitty wal-mart socket set...) 

Going out to sears to get a decent socket set and wrench now...

EDIT: yeah, looks like I got the right bolt... just being a dog to loosen :-/


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## ConKBot of Doom (Jul 24, 2006)

sory for the triple post, but I cant edit my last one...

I got it all worked out, put the new alternator in, and replaced all the drive belts, and yeah, that 14mm bolt on the back of the power steering pump is the one you gotta break loose. Took a long handle socket wrench (the handle came down past the axle) and I hammered on it with a dead blow hammer, finally broke free. Took all that even with pb blaster on it, hate to see what it would have taken without the PB blaster.

If anyone else has to change their alternator:
1.take off negitive battery terminal
2. take out your passenger side radiator fan
3. take off your passenger side splash gaurd (bottom)
4. disconnect the wires to the alternator (1 plug, and 2 bolt on connections
5. remove the tensioner lock bolt
6. move the coolant reservoir (it just pulls up) for me it fit well between the radiator and the front of the car.
7. loosen the driver side pivot bolt but dont take it out
8. get under the car, and remove the passenger side pivot bolt
9. rotate the alt. up and take off the belt
10. back on top, remove the driver side pivot bolt, and carefully remove the alternator (dont smash your radiator... probably should watch out with the socket wrench too)
11. reverse the process (you'll have to unscrew the tensioner most the way to get the lock bolt to fit back)

The mess begins when you try to replace belts too


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## Dan9 (Sep 18, 2004)

Batt light went away when I changed the alty
\
Yeah and for me the brake light still did not go away, I am sure it is a bad contact at the little switch under the e-brake handle. Before putting stuff back together Im'a clean it up a bit then the light should go back off (it occasionally does)



D


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