That resistor is built into the wire and yes an auto parts store will have a generic replacement. It's called a ballast resistor. To verify the need, the voltage at the coil should be 6-8 V. If it is 12 V or the same as battery voltage to ground, you have to get the resistor. Failures of the resistance wire usually result in an open circuit. I've never heard of one shorting so some one has done you a dis-service. The replacement circuit will be from the ignition switch, a redwith a green tracer wire, thru the fire wall (you will have to make a new hole, make sure it don't short out as in use an extra insulating sleeve) to the ballast then to the coil. Disconnect the red-green from the pink (the resistor wire) under the dash and tape the pink wire's connection. Don't disconnect the existing wire from the coil as it will provide 12 V to start.
Jim
Jim

 

To check the voltage, do I need to put the voltmeter on the positive wire on the coil and turn the key?

 

Both, only as a sanity check. After you get the car running, make sure you can turn it off. Somewher in another thread, Soaring said you should read 9V at the coil. That would be in a running mode. If you are checking voltages when the car is not running, it will be less. In any case, check the battery voltage to verify what your meter reads then do the coil check..
Jim

 

DenDen

If using pertronix with stock coil you need the resistor but if you upgrade your coil to pertonix master blaster instructions that come with coil tell you to bypass resistor and go 12 volts.

 

I just checked Advanced Auto parts website. They do sell a coil resistor, I assume this is the same thing.

 

den den i am sure the pertronixinstructions say tobypass the ballast wire you need constant 12V nominal and if you are unlucky the ballast wire will result in the pertronix not working as the V is to low.