the only way the dash lights would be affected is if they weren't changed to 12V bulbs, easy fix - for the gas gauge, if it always only reads full it's likely been fried already by not having the dropping resistor .... those resistors don't get hot enough to be a big concern, usually just mounted under dash in the line from power source to gauge [see EL110 here]

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