Fitment notes: Side post terminals standard on GM full-size vans; battery located under hood on passenger side
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Every control module on the 1981-1989 GMC Rally Wagon — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
Instrument Cluster (IPC)2.0 hr R&Rno coding1987-1989 with electronic cluster
📍 Behind instrument panel in dash
⚠️ Most 1981-1986 clusters fully analog. Electronic versions communicate with ECM via serial data for some gauges.
Electronic Brake Control Module (EBCM)1.5 hr R&Rrelearn only +0.2 hr1989 only with optional ABS (Delco Moraine VI)▸ programming details
📍 Mounted on frame rail near master cylinder
🔧 Tech 1
⚠️ ABS introduced very late in generation, rare option. Requires brake bleeding and system initialization after replacement.
📍 Behind right kick panel in passenger footwell area
🔧 Tech 1 with PROM/MEMCAL chip
⚠️ TBI (Throttle Body Injection) systems standard by 1987. Programming via physical PROM/MEMCAL chip replacement.
Radio (Radio)0.8 hr R&Rno coding
📍 Center instrument panel
⚠️ Analog radio; no programming required.
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 1984 GMC Rally Wagon 350ci V8 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.