Volt Meter Fluctuation Causing Car To Stop Running...

[dheim25]

So, I'm having a problem with my '92 Sentra XE battery/alternator/ground wiring. I start the car up perfectly fine every single time but as soon as i turn on my heat or lights I'll get this fluctuation in volts causing the car to shudder and sometimes stop while i am driving. Now, the weird thing is, I can turn on my radio with a subwoofer and amp play it as loud as i want, but I won't get the fluctuation that I do with the heat or the lights. If i run a combination of the lights and the radio or the radio and the heat, I'll get the fluctuation. I have a volt measurement of about 14.5V with the car running and no accessories on. It measures about 14.2V with my radio, sub, and amp running. But, with my heat and/or headlights on it can drop as low as 12.3V which is no where near where it should be. Would there be a problem with one of the grounded wires in the dash that causes this fluctuation? To me, that wouldn't make sense because the grounded wires for the heat and lights should be two totally separate wires and two separate grounding points. Could there be a fuse blown somewhere or not seated correctly in the housing unit that is causing this shorting?

I really appreciate the replies to this! I'd love to get this figured out so I can not be so worried when I'm driving if its going to leave me sit in the middle of a snow storm again....

[AZhitman]

Welcome aboard.

I'm going to guess this is a major ground issue - typically not under the dash, but under the hood. I'll bet you did a great job of grounding that audio system, but your factory ground strap is toast.

[dheim25]

That's what my dad and I were assuming that it was a ground issue under the hood. But, now the challenge is to find that ground point that is loose/causing the problem with out having to tear the whole thing apart.

Thanks!

[AZhitman]

Follow from the neg cable on the battery, up the harness.

Also, it never hurts to make a new ground strap from the neg terminal to the chassis (a good, bare metal spot) and run one from the block to the same spot. $2 well-spent.