HVAC vacuum hose colors need to be revised for the service manuals referenced (Section 8A).
The attached figures show the correct hose color referencing.
Figure 1, (Pg. 65-1) - Chevrolet 'L' Series Figure 2, (Pgs. 60-1, 65-0) - Chevrolet 'J' Series
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.