4 pin ECU doesn't work. Old 5 pin does.

Depends on the year and perhaps engine, which the OP didn't bother to mention. For anyone that needs to rewire anyway, I suggest dropping the Mopar ECU and ballast and changing to a GM 8-pin HEI module & coil (85-95 V-8 trucks). Simpler wiring, hotter spark, and more reliable. TrailBeast here sells as a kit for those who fear junkyards. While in there, smart to add a relay off BATT+ so you don't rely on the bulkhead connector resistance, and insure you ground the module well - not a rusty sheet-metal screw, applies to Mopar ECU also.