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Every control module on the 1965-1974 GMC C2500 — where it lives, replacement time, and what it takes to program a replacement.
Ignition Control Module (ICM)0.5 hr R&Rno codingLate 1974 models with High Energy Ignition (HEI) option only
📍 Distributor-mounted or firewall-mounted
⚠️ Fixed-function semiconductor switching device introduced very late in 1974 production on some models. Not programmable; no diagnostics beyond basic electrical testing. Most 1965-1974 C2500 used conventional points-type ignition with no electronic module.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 1967 GMC C2500 292ci I6 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.