Mugsy,
Does your truck have an amp gauge? There is a resistor in the circuit to the "R" terminal. Bad resistor?? If not, there should be two wires going to the "R" terminal. One is white/orange/purple coming from the bulkhead connector. The other is yellow going to the coil from the "R" terminal. There should be a single purple wire on the "S" terminal, this is your crank signal wire(hot in crank). Look for the pink wire at the ignition switch connector (changes to the w/o/ppl at the bulkhead connector). This should be your "run" voltage. If you're running HEI, you should have 12v from the "run" circuit to the "R" terminal. Do you have two wires at the "R" terminal? You can try running a redundant wire for the "run" circuit from the switch to the "R" terminal and see if this eliminates your concern.
HEI should have 12v at the "R" terminal, translating into 12v from the yellow (coil)wire coming out from the "R" terminal. Make sense??
Hope this helps.
Jim Sgrig
