The Stovebolt Site Forums The Shop Area The Electrical Bay Voltmeter Question

Is it correct that the voltmeter (49 Chev 1/2 ton) is nothing more than an in line device that measures voltage in the electrical system? Therefore if I am eliminating the gauge,(replacing with aftermarket)can I just connect all of the existing wires going to the exisitng gauge together? The new gauges will get their power off of a new line from the ignition terminal on the ignition switch.
Thanks,

Yes

Voltmeter? I though those models had an ammeter! A voltmeter would be installed from hot to ground, and connecting those wires together would create a dead short!
Jerry

Hotrod, you're right it is an ammeter. In my case though, the connections I'm asking about are all "hot", starter switch to ammeter, ammeter to fuse block and ammeter to alternator, so I think I'm still ok, I think.

Hrockwell:
Assuming it is an ammeter that your are considering replacing with an after-market voltmeter, it may not be a direct replacement. Ammeters measure current flow and often (not always) are to some degree in-line with current flow. Voltmeters measure a voltage (or potential) drop across a resistance. Many times they are set up to measure from some point in a circuit to ground. Ammeters and voltmeters measures different things, even though those things are related, current and voltage respectively. As a result they are usually wired differently. However, replacing the ammeter with a voltmeter is not a big deal, you may just need to re-wire a little bit depending on your current setup.

OK, now we're on the same page! Most older ammeters have a "shunt" built in, which carries most of the current, bypassing the meter movement, which only needs a few miilliamps to function. Simply tapping all the wires onto one terminal, or eliminating the meter and replacing it with a voltmeter isn't a problem. If you're going to an aftermarket ammeter, you'll need to follow the manufacturer's wiring diagram to make it indicate properly.

As long as your voltmeter (if you're using one in place of an ammeter) is connected to a source of straight battery voltage, such as the "ignition" or "accessory" terminal of the ignition switch, it should read battery voltage anytime the switch is on. Connect the other voltmeter lead (usually the "-" terminal) to a good ground, and you're in business!
Jerry

Thanks all for the guidance. I'm replacing my stock gauges with new units from Classic Instruments. The new gauges are pretty straightforward to hook up. I was concerned about making sure that the rest of the electrical system is still in order.