Re: Volt Meter
Amp meters are connected in SERIES with supply and indicates an increase or decrease of current (charge or drain) in the circuit. Therefore it can allow a significant amount of current to flow thru the wire if it's shorted. (read as potential for FIRE) However, FACTORY wired ampmeters rarely cause problems. Their circuits are designed to be well insulated and properly routed.
Volt meters are in PARALLEL to the supply and indicate amount of voltage present at the connecting point. Requires very little current to operate and can quick-fused to prevent heating the wiring if shorted.
Us old timers are used to ampmeters and some prefer them. They do give an actual status of the supply circuit and the alternator (gernerators in the old days). Obviously, if the current meter (ampmeter) indicates a constant negative flow of current, things won't go well for very long.
Voltmeters are a relatively recent addition to cars. They are cheaper to incorporate, easy to fuse for safety and easier for the average person with little to no electrical knowledge to understand. A volt meter can also indicate that the alternator is not funtioning or putting out 13.9 to 14.3 (nominal) voltage. If it is only showing 12 volts or less when the engine is running, it too is a good indicator that something is amiss in the charging circuit and you will be walking soon. An HEI distributors like to see a solid 12 volts at all times, not 11 or 10. However, a bad battery can still show 12 volts on a voltmeter in an unloaded condition.
Both gauges can co-exist and function just fine. No need to remove or disconnect either if they are wired and funtioning correctly. However, if their function and indications aren't clearly understood, you're better off with an idiot light. That's why they were invented. No offense intended to anyone, just MHO. My wife's Jeep has gauges. She has no clue how to interpret them for a potential problem and doesn't want to learn. But if a bright RED light comes on, she know's she has a problem. (either in the car or from the cop behind her ;-))