Wiring diagrams

These are a series of 'aftermarket' wiring diagrams I was given that someone downloaded. They are not as complete nor as detailed as the GM factory diagrams, so you can still justify the expense and hassle of the Helm manuals. However, these can help you for quick problems and to give you a general idea of how systems work.

Documents are in Adobe Acrobat (PDF) format. They range from 20K to 100K in size, so they're all easily downloaded over even a dialup connection.

These first two are generic, not model-specific info on how to use the diagrams; the others are separated by year and type. 'Engine' wiring will generally cover the distributor and ignition switch only; the 'chassis' diagrams include most systems on the truck. (I was bummed to find that diesels aren't covered, but this is another good reason to get the real factory manuals, or check out the CUCV stuff.) There is some duplication; considering that each is at most two pages, download and print them both out.

Finally, if you don't know the difference between the C-K and R-V series trucks, check out my Blazer History page for details.

Common wiring symbols
How to interpret wiring diagrams


1969-1972

69 - 72 Chassis.pdf
69 - 75 Chassis.pdf
69 - 79 Engine.pdf
70 - 72 Chassis.pdf
70 - 76 Chassis.pdf
70 - 78 Engine.pdf

1973-1980

70 - 76 Chassis.pdf
70 - 78 Engine.pdf
73 - 74 Chassis.pdf
73 - 76 Chassis.pdf
75 Chassis.pdf
76 - 77 Chassis 1.pdf
76 - 77 Chassis 2.pdf
77 - 79 Chassis 1.pdf
77 - 79 Chassis 2.pdf
78 Chassis 1.pdf
78 Chassis 2.pdf
79 - 82 Chassis 1.pdf
79 - 82 Chassis 2.pdf
79 Engine.pdf
80 - 82 Engine.pdf
80 Chassis 1.pdf
80 Chassis 2.pdf

1980-1991 (old body style)

79 - 82 Chassis 1.pdf
79 - 82 Chassis 2.pdf
80 - 82 Engine.pdf
81 Chassis 1.pdf
81 Chassis 2.pdf
82 Chassis 1.pdf
82 Chassis 2.pdf
83 Chassis 1.pdf
83 Chassis 2.pdf
84 Chassis 1.pdf
84 Chassis 2.pdf
85 Chassis 1.pdf
85 Chassis 2.pdf
86 Chassis 1.pdf
86 Chassis 2.pdf
87 Chassis 1.pdf
87 Chassis 2.pdf
88 - 90 R-V Chassis 1.pdf
88 - 90 R-V Chassis 2.pdf
91 R-V Chassis 1.pdf
91 R-V Chassis 2.pdf

1988-90 (new body style)

88-90 C-K Chassis 1.pdf
88-90 C-K Chassis 2.pdf