Why Amp Meters in FSJs Can Cause a Fire:

1. Full Current Flow: The ammeter in FSJs is wired in series with the electrical system. This means the primary current of the Jeep flows directly through it. Given the rugged usage and sometimes demanding electrical needs of these vehicles, the potential for overload and overheating is significant.

2. Aging Wiring and Connections: With vehicles from this era, wear and tear is a given. The FSJ's wiring and connections associated with the ammeter can deteriorate, corrode, or loosen over time. Since the ammeter handles the Jeep's total electrical load, a degraded connection can result in high resistance. This high resistance can generate excessive heat, which, combined with the old wiring insulation typical of this era, raises the risk of a fire.

3. Limited Fuse Protection: The ammeters in these FSJs typically lacked adequate fuse protection. In the event of a short or malfunction, there's no quick-acting fuse to cut off the flow, allowing potential overheating situations.

Benefits of Converting to a Volt Meter in FSJs:

1. Enhanced Safety: The primary advantage of a voltmeter in an FSJ is safety. Since voltmeters are connected in parallel with the circuit they're measuring, they're not handling the Jeep's primary current, thereby minimizing the risk of overheating and potential fire hazards.

2. Simplified Wiring: For FSJ owners, converting to a voltmeter can simplify the wiring process. You don't have to maneuver the Jeep's primary electrical wires through the gauge, which reduces potential failure points.

3. Immediate Feedback: A voltmeter offers FSJ drivers a direct insight into the system voltage. Especially in off-road or challenging terrains where these Jeeps often find themselves, being informed about the health of the charging system is vital. Abnormal voltage readings can indicate issues with components common to FSJs, like the alternator or the battery.

4. Durability for Rough Use: Given the rugged usage FSJs are often subjected to, voltmeters, especially contemporary ones, are more resilient. With fewer (or no) moving parts if they're digital, they can withstand the mechanical jostles and vibrations that come with typical FSJ adventures better than older ammeters.

In wrapping up, for FSJ enthusiasts, making the switch from an ammeter to a voltmeter isn't just about modernizing a component; it's about enhancing the safety and reliability of a beloved classic. Given the unique demands placed on Full Size Jeeps, it's a conversion that offers both peace of mind and practical advantages.