1977 280Z Voltage gauge "Always On?"

[sblake01]

The aren't wires per se. They are fusible links. The front box should have an 80 amp link closest to the fender and the other three are 50 amp as in this picture from the Alantic Z site.

[Zedrally]

Easiest method of turning it off is to detach the +ve battery lead.

Very counter-productive though. Best leave it as use it as it was design for.

[FastWoman]

Awolfe, what everyone else said. I, too, was surprised the V meter always stays on. IMO the current draw isn't infinite or near-infinite, but it is very small in relation to the huge battery. It shouldn't pose any significant battery drainage problem, any more than your clock or the memory on your stereo. In fact the battery would probably lose voltage faster on its own than through drainage by these tiny circuits.

You can get fusible link wire from your local auto parts store. Off hand, I don't know the proper gauges or ampacities, but that info is buried throughout this thread:

http://www.classiczcars.com/forums/showthread.php?t=35588

[SteveJ]

You can still get the proper fusible links here.

[Walter Moore]

I didn't realize that the voltmeter in the later cars was always hot. At first glance that would seem like a problem, however generally analog meters have an input impedance of 10,000 to 20,000 Ohms per volt, so with the scale showing a maximum reading of 16V that comes out to somewhere in the range of 160,000 to 320,000 Ohms. At 12V that calculates to a steady state load of 38-75 micro Amps. At that discharge rate it would take more than 10 years to discharge an 800CCA battery.

So I would say it isn't a cause for concern.

[Zedrally]

Somewhere I remember reading that the voltmeter was actually a "Battery Condition" meter.

Hence the coloured segments on the scale.

[wa5ngp]

I switched out my ammeter in my 73 to a voltmeter from a 280. To me the voltmeter tells me a lot more about battery and alternator condition. and yes. It shows on all the time.

Just lately my autozone lifetime alternator went bad. I've got a zx one that I'm going to go back with. its autozone lifetime too. came from my rustbucket 81zx.

don

[awolfe]

Thanks for all the quick and great advice, I decided to keep it wired as is. The previous owner was a complete nut job and made such a mess of things that i spent 2 days completely rewiring the car.

BTW, does anyone know or have a picture of the proper turn signal/light & wiper control location on the steering colum. I forgot to mark its location when i removed it to resoldier a couple of broken wires.

[SteveJ]

Put the cover back over the steering wheel. It becomes obvious where the combo switch and turn signal switch need to be mounted.

[IdahoKidd]

Personally, I much prefer an ammeter. I can tell when the battery is dead, knowing that it is headed that way is of much for help.

[sblake01]

I think you'd be in the minority. An ammeter can only measure the amount of current to the battery for recharging purposes while a voltmeter directly measures the entire charging system's performance. Has any auto manufacturer even equipped a vehicle with an ammeter since the mid 70s?

[FastWoman]

Leonard, when your voltmeter reads anywhere north of, say, 13v, your alternator is maintaining the charge. So if my voltmeter were to drop from its usual 14.5 to maybe a steady 12.5, irrespective of RPM, I'd know I was slowly discharging and that my alternator wasn't doing anything. Besides that, there's a little alternator fault light on the 280's voltmeter, and that will probably grab your attention faster than an ammeter needle.