[jstluise]

1994 Nissan Sentra LE

A few weeks ago, my battery dummy light (and failsafe brake dummy light, since they are on the same circuit) started coming on every once in a while for a few seconds. Some days it would not do and and others it would do it once or twice a day, for maybe a couple seconds or maybe stay on for a minute. Very sporadic. It seems to come on when the car goes over a bump, which seems to indicate a loose connection, but it also come on just driving on a smooth rode. When the lights come on, there is a drop in power for sure (lights, fan, etc).

Now I am just looking for some direction on what actually can cause these dummy lights to come on. I've checked all the grounds that I can find, and all are tight and clean (I haven't taken them off, but they look don't look corroded). Battery is good and connections are good there also. I've unplugged some of the connections for the alternator while the car was running, but I couldn't get the lights to do the same thing.

I did replace the alternator maybe 8 months ago after it went out...the lights actually came on the same but stayed on, and I was able to diagnose the problem (bad alt). So I replaced the alternator and everything was good up until a few weeks ago. Could it be the alterator?

This problem is frustrating since it doesn't do it all the time...so diagnosing it is going to be a challenge until it does it more frequently or stays on. Any ideas? Maybe connections to check that would be causing this problem if they were loose? I really can't take the alternator in to test it since it doesn't do it all the time.

Any help would be appreciated! Thanks!

 

[M.J.]

It could be your Alternator

I replaced my alternator a few years back, and then almost a year later that I did it, I had to replace that one.
The rebuilt/remanufactured alternators out there are not always of the best qaulity and on those componets they really can go at any time.
Provide that you checked all your connections, grounds,V belt, load test battery, checked wires for continuity, resistance, and relays, it sounds like your alternator may have an intermitten problem and will sooner or later go.
I have heard of that part doing what yours is doing.

 

[jstluise]

Thank you for the response.

I do have a year warranty on the alternator, but I hate just throwing parts at the thing because I don't even know for sure if that is what it is. I'd be pissed if I got a new one in there and it didn't fix the problem. I've been waiting for something to go out so I can diagnose the problem, but it is still doing it intermittantly.

A couple weeks ago I tried to mess with it to see if I could get the dummy light to come on. I couldn't do it. Unplugging wires here and there, from the battery and alternator, I couldn't get the light to come on at all. Even disconnecting the alternator completely didn't even change anything, which I thought was odd. There is something in the circuitry that causes that dummy light to go on but I just don't know what it is. I mean, when the alt went out the first time the light was on, so it must be something within the alternator which triggers that light...I dunno.

Maybe I'll swap out the alt. We'll see how that will go down at the autoparts store since they'll probably test it and find nothing wrong with it.

Thanks again.