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.
"Cab, Engine and Chassis Wiring MD-6430"
This item is original.
11.00 x 8.50 x 0.10 inches
Covers medium duty GMC steel tilt cab truck models with the 6V-53 Detroit Diesel engines, also known as TV. To verify that this is the correct diagram for your truck, you can check your VIN code. The 1st digit should be a T for the steel tilt cab, the second digit should be a V for the 6V-53 Detroit Diesel engine, and the last six digits should be between 170001 and 500000 to indicate the 1971 model year.
1971 Detroit Diesel Engine 53 Series
1971 GMC Series 7500-9500
1971 Detroit Diesel Engine 53 Series 1971 GMC Series 7500-9500