Model Condition Price Qty  
MD10049 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 MD-10049 / MD-10051"
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Covers medium duty Chevrolet and GMC steel tilt cab truck models with gasoline or diesel engines, also known as TE/TM/TV/WV 60003, 65003, 65013, 75013, and 80013. To verify that this is the correct diagram for your truck, you can check your VIN code. The 2nd digit should be a T or a W for the steel tilt cab, the third digit should be an E for the V8 gas engine or an M for the V6 gas engine or a V for the 6V-53 diesel, and the 6th digit should be an 4 to indicate the 1974 model year or a 5 to indicate the 1975 model year.

This diagram covers all M and V engine vehicles. This diagram covers 1975 models built prior to March 1, 1975. If you have a 1975 TE model, to find out if yours is a mid-year model (built after March 1, 1975), check the last six digits of the VIN, which should be smaller than 590000 for GMC or smaller than 140000 for Chevrolet. See the mid-1975 diagram if the last six digits are larger.
1974-1975 Chevrolet 40-60 Medium Duty
1974-1975 Chevrolet 70-90 Series Heavy Duty
1974-1975 GMC Series 4500-6500
1974-1975 GMC Series 7500-9500
1974 1975 Chevrolet 40-60 Medium Duty 1974 1975 Chevrolet 70-90 Series Heavy Duty 1974 1975 GMC Series 4500-6500 1974 1975 GMC Series 7500-9500