This is the original wiring diagram printed by GM for dealer mechanics. You can follow the wiring in your truck from bumper-to-bumper. It will help you to understand connector configurations, and locate & identify circuits, relays, and grounds. Although the schematic is in black and white, the color of each wire is noted. You will not find this diagram in your shop manual. The schematic measures 8.5" x 11" when folded up, and opens up to 11" by 38". The diagram pictured is an example of this type when folded, but is not the actual diagram for your vehicle. Buy now for the best electrical repair info - the factory wiring diagram.
1979 Truck Wiring Diagrams Medium and Heavy Duty Models MD-17867
This item is original.
11.00 x 8.50 x 0.10 inches
This book covers 1979 GMC Brigadier and Chevrolet Bruin also known as J-9, equipped with the 6V-92 diesel engine. See my other items for other engines. To verify that this is the correct diagram for your truck, you can check your VIN code. The 4th digit should be a C for the heavy duty steel conventional cab, the 5th digit should be a J for the 6V-92 engine, and the 6th digit should be a 9 to indicate the 1979 model year.
1979 Chevrolet 70-80 Series Heavy Duty
1979 GMC Series 7500-9500
1979 Chevrolet 70-80 Series Heavy Duty 1979 GMC Series 7500-9500