1975 ford f 100 ranger xlt, when testing the coil with a test light positive side stays bright, the negative side dims the light greatly and does not blink. magnetic pick up points in the distributor. so where do i go to track this down

 

Welcome to FTZ. Most times your would check a coil with a DVOM (Digital Volt Ohm Meter), Google how too. You leave a lot of info out as far as "No Spark" goes. Is this a Distributor that was once points and condenser, with a electronic unit replacing the points an condenser ?? Is it a Ford Dura Spark ignition System, which the stock 1975 truck might have had?? So, if you pulled the coil wire out of the distributor cap and held it a 1/4 inch or less away from metal on the engine And someone would crank the engine over for you, you have no constant spark jumping from the wire?? Cap