1996 Maxima SE - electrical problem? where to start looking?

[llungster]

My '96 Maxima SE just started exhibiting some strange electrical behaviors and I'm hoping someone can point me to some areas to look.

It started with the wipers slowing way down as I was driving to work. I though the wiper motor was dying as this had happened once long ago. But then it picked up speed and appeared normal. I forgot all about this incident.

A week later I noticed the rightmost fluorescent segments of the clock display were a little dim but I didn't think much of it since the car is over 10 yrs old.

Finally, one day on the way home from the office, the radio starts to fade and get all sorts of static; until to practically went dead. That's when I realized the clock was visibly dimmer. I figured there was an electrical problem and tested this with the turn signals. Each time I used the turn signal, the tack would jump for an instant and the airbag light would come on - almost as if the car had been re-started. But no other lights on the panel came on. The wipers moved light molases. It was getting late so I rushed home, avoiding the use of my headlights in case that would make matters worse. On the highway exit ramp, I noticed that my clock came back to full brightness and lo and behold, everything was fine again.

I took it to my local mechanic the next day who plugged in a battery tester to find my 5 yr old DieHard was bad; and the alternator was fine. So I replaced the battery. I wasn't convinced that the problems I saw would be battery related but I figured that as long as the battery was suspect, the tech wouldn't look further. Fair enough. This was last week.

Things looked good until today when I noticed the clock was a little dimmer on the edges again (like it was before) but the radio was fine. Then for a few seconds, the battery light and seat belt light came on; no other lights. These went away and have not come back the rest of the ride. The wipers seem a little slow to me but that's hard to say without a direct side-by-side comparison with another identical car.

So far, none of this has caused any loss of power in the engine - the car is driveable. It starts fine without complaint. The only time the engine acted up was when the tach did that jump I mentioned earlier. I'd like to get this fixed since it's no fun driving with bad electricals ! But I can already see my local mechanic telling me that everything is fine - the only time I've seen a problem has been on the highway; never on local roads. And it's so intermittent that it's hard to reproduce.

So I'm thinking it's probably something coming loose or maybe a wire going bad from corrosion? Or something that, when loose, come back to form when I take exit ramps (body lean?). I've had the battery light, seatbelt light, airbag light, wipers, turn signals and stereo affected but none of the other lights in the instrument panel.

Does anyone have any hints on where to start looking for a problem? TIA

[NM50]

Check the alternator output.13 1/2 to 14 1/2 is the norm.Also check the airbag system for codes.It may have set one for low voltage.This may be a failing alternator.

[mrbizness1]

I believe NM50 is correct. The alternator could be on its way out. I would check the battery. It might slowly be losing it charge because of the alternator. On my 96 maxima when the alt. was starting to go the alt and brake light came on. The first alt. replacement shut the lights off but I still had no crank problems a day later. That's when I decided to carry a multimeter with me. Sometimes it would put out 14.2 to 14.5 volts, then I would shut it off and restart and it was putting out 11.5 volts. The diodes inside it were bad. I had a dealer install a Nissan rebuilt the second time and its been good for almost 2 years. I put a Autozone rebuilt in my altimawhich has been good for a year. good luck

[llungster]

Thanks for the reply. How do I see the airbag codes? Is that something only the tech at the shop can see via his diag tools?

When I had my battery replaced, I was told the charging system/alternator was fine. But of course, my fear is that the problem is very sporadic which is seems to be.

[llungster]

Thanks mrbizness1. I wish I could connect a multimeter to the car and get the reading live during my commute.

Here's a dumb question - does the battery light/indicator reflect a low voltage on the battery, the alternator or both?

I've never spent time on a car's electricals (just know enough to stay clear of them 'less I destroy my car ) so forgive my ignorance. Is the alternator's output reflected at the battery's terminal or is the power from the alternator isolated from that of the battery once the engine is running? Or put another way, what's the relationship between the 2 sources of power once the engine is running? I assume the battery is constantly being recharged but are there certain functions that are somehow isolated to one source of the other (if possible)? I ask because I'm still perplexed at the behavior that I've seen thus far and the engineer in me can't rationalize it.

thanks!