What year truck? The ceramic-shielded resistor was only used for a short time, then they went to a nickel-chrome alloy resistance wire from the ignition switch to the coil. "bypass" voltage is provided either from a second (copper) wire from the switch to the coil called "Ign 2" which is hot with the key in the start position, or by a bypass wire from a small terminal at the side of the stomp-start switch to the coil (+) terminal.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!