Where was the jumper wire inserted? Assuming it was from the battery to the coil it definately indicates that the problem is in the wiring that provides power to the coil. Amp meter is a good place to start although if the headlights work I believe they are fed through the amp meter. My bet would be the ignition switch, he should be able to check for power to the switch and power to the coil coming out of the switch to isolate it.
