1992 GMC Forward Control 6.2 J, AutomaticFACTORY OEM SERVICE PROCEDURE

Control Units

CONTROL UNITS LOCATION

Component Location
Audio Alarm Module Behind dash, below fuse block.
Check Engine Light Driver Module On left side of steering column.
Cruise Control Module At rear of parking brake bracket.
Daytime Running Lights (DRL) Module Behind left side of dash.
Diode Array Module Behind left side of dash, in dash harness.
Electronic Control Module (ECM)
4.3L (VIN Z)
"G" Series Under driver's seat. See Figure.
"P" Series Under driver's seat. See Figure.
5.0L (VIN H) & 5.7L (VIN K) Under driver's seat. See Figure.
Electronic Control Module (ECM)
"P" Series 5.7L (VIN K) Under driver's seat. See Figure.
"G" Series 7.4L (VIN N) Under driver's seat. See Figure.
"P" Series 7.4L (VIN N) Under driver's seat. See Figure.
"G" & "P" Series 6.2L (Diesel) Under driver's seat. See Figure.
Electronic Delay Module Behind left side of dash.
Elec. Spark Control (ESC) Module
4.3L (VIN Z)
"G" Series Under driver's seat. See Figure.
"P" Series Under driver's seat. See Figure.
5.0L (VIN H) & 5.7L (VIN K) Under driver's seat. See Figure.
"P" Series 5.7L (VIN K) Under driver's seat. See Figure.
Electronic Spark Timing Module On distributor.
Glow Plug Controller
"G" Series On left side of engine.
"P" Series On top rear of engine.
Hot Fuel Module
5.0L (VIN H) & 5.7L (VIN K) Under driver's seat. See Figure.
7.4L (VIN N)
"G" Series Under driver's seat. See Figure.
"P" Series Under driver's seat. See Figure.
Keyless Entry Module Behind right side of dash.
Low Coolant Warning Module Behind left side of dash.
Power Door Lock Delay Module To right of steering column.
Powertrain Control Module (PCM)
"G" Series Under driver's seat.
"P" Series Behind left side of shipping panel.
Rear ABS Module On left side of engine compartment.
Transmission Control Module
"G" Series Under driver's seat.
"P" Series Behind left side of shipping panel.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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