1979 Ford Bronco/F100-F350 Starting & Ignition System Troubleshooting Guide

This page from a 1979 Ford truck/Bronco owner's reference booklet covers the Starting and Ignition Systems. The Starting System section explains that the system consists of the starter, starter relay, and ignition switch, and provides step-by-step trouble-shooting for symptoms such as slow cranking, relay chatter with no crank, relay clicks but no crank, and starter spins without cranking (humming noise). Remedies include checking battery charge, cleaning posts and cable clamps, cleaning the starter relay connector (red wire with blue stripe), jumpering the relay terminal to the battery positive terminal, and testing the neutral start switch at connector C1015 on automatic transmissions. A photo shows the Neutral Start Switch Location. The Ignition System section describes the transistorized ignition module, ignition coil, breakerless distributor, and spark plugs/wires, and how the magnetic pickup and armature control primary current. Trouble-shooting includes a caution to disconnect the air supply line on catalytic-converter vehicles before cranking with ignition off, spark tests using a spark plug with side electrode removed, aligning the rotor with the pickup (Armature Pickup Alignment diagram), voltage checks on the red wire to the module (within 1.0 volt of battery), coil BAT terminal tests, and module ground repairs for 6-8 volt readings. Photos illustrate jumping black and green wires and conducting a coil test.