"if the ammeter in the dash carries all the truck current" [you need to "shunt" the ammeter] .... you will not have any problems with the TF gauge if the wiring is sound and according to the factory diagram, it carries only the current that charges the battery .... OTOH an ammeter doesn't tell you as much about the condition of the system, and with a LOT of electrical goodies added, a voltmeter is considered better

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot