Condition Price Qty  
Very Good $29.00
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 - HN/JN-9500 MD-7749"
This item is original.
11.00 x 8.50 x 0.10 inches
MD7749 1971
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This diagram covers 1971 GMC 9500 Conventional models also known as HN or JN, equipped with the Cummins diesel engine.To verify that this is the correct diagram for your truck, you can check your VIN code. The 1st digit should be either an H or an J for heavy duty conventional cab, the 2nd digit should be an N to indicate the Cummins NHC 250 or NH 230 diesel, and the last six digits should be between 170001 and 500000 to indicate the 1971 model year.
1971 GMC Series 7500-9500
1971 GMC Series 7500-9500