richleroux

my daughters 95 maxima has stopped charging.... at first I believed it to have a short as we were having starting problems. we replaced the battery at which time I checked to be sure the alternator was working, I discovered it had only battery voltage at the battery however when I checked the voltage directly off the alternator I found it was producing 15 volts at idle. I checked underhood fuses all of which appear to be good. Im thinking there must be a fusible link or something like that somewhere between the battery and alternator. anyone that can tell me anything about it before I go tearing stuff apart in the Wyoming cold?

KP11520

Does the Tach work?

If not, there's a fuse under the dash in the box. It's in the left bank closer to the bottom. IIRC, it's 7.5 amps. If it's out, the gauges mostly don't work and the charging system doesn't engage.

If that's the problem, something shorted somewhere and it will most likely happen again. Now the fun starts.

Don't ask me how I know.

Are you sure the alternator was putting out 15 volts? 14.2 is supposed to be the governed max. That might also be a cause.

richleroux

Well the tech worked sort of last I knew, it's never read correctly since we owned the car but on start up would do it's normal sweep, just never actually displayed the correct engine rpms, I haven't checked since this problem began but I'll b sure n check that fuse before anything else as well as all the rest under the dash, as for the voltage I was reading it off my battery load tester which has just a old style needle gauge on it but it was reading upper 14s to lower 15s on the high side of the charging ok markings

The Wizard

iTrader: (43)

Did you test it with a load on it? Meaning, turn on everything in your car like headlights, stereo, rear defrost, heater etc and see what the voltage says...


15V is too high. The VRM could be bad.

Normal range is 14.1-14.7. At max load it's 13.5.

It will be a dead giveaway if the VRM is bad if lights/accessories are on and your voltage doesn't drop at all.

Need more info.......

richleroux

I did put a load on it sort of... Had the headlights on and the blower motor running while I put load on it with my battery tester however I was hooked up at the battery when I did it not at the alternator, but the voltage loaded or not stayed firmly at 12. I intend to do further testing before performing any actual work, so ill definitely check voltage at the alternator with a more accurate meter while putting a load on it. I assume the vrm you're referring to is a voltage regulator module...and that the system may be shutting down due to high voltage? I figured like most vehicles that would be in the alternator itself and would not allow itself to put out to much voltage. Do these have external voltage regulators?

Decimus Meridias

iTrader: (5)

This may or may not be related, but several years ago my car wouldn't charge. I replaced the alternator and still wouldn't charge. It ended up being one of the blue relays next to the fuse panel under the dash. I believe there are three of them. They are all the same (I think), so try swapping them around and see if your car starts charging. Assuming you have a bad relay, this will cause other systems not to work (turn signals, random lights, etc.), but its a really easy way to troubleshoot until you can pinpoint the bad relay and replace that one. Hope that made sense and that this helps.