Subject: Heat Damage to Engine Wiring Harness
Model and Year: 1968 Passenger Vehicles with 396 or 427 Cubic Inch Engine
Source: Chevrolet Dealer Service Technical Bulletin
Bulletin No: 68-T-25
Section: VIy
Date: Feb. 19, 1968
TO: ALL CHEVROLET DEALERS
The engine wiring harness on some early production 1968 passenger vehicles equipped with either the 396 or 427 cubic inch engine may be subject to exhaust manifold heat damage harness wires are not properly routed through the retaining clip located on the starter solenoid. Reports have indicated that the yellow colored ignition or cranking by-pass wire, which attaches to the solenoid terminal closest to the exhaust manifold, is the wire most often damaged by exhaust manifold heat. To prevent damage, the wire must be routed "loop-free" through the solenoid retaining clip to the solenoid terminal.
Effective November 27, 1967, the assembly plant is repositioning and taping the wiring harness on all Corvettes with either the 396 or 427 cubic inch engine as shown in figure 1. Proper routing of the engine wiring harness through the retaining clip on all other passenger vehicles with the 396 or 427 engine is being more closely maintained at all assembly plants.
If heat damage to the engine wiring harness is encountered on subject 1968 Corvette models in the field, the harness should be taped as shown in figure 1. If harness replacement is necessary, the new harness should be similarly taped at the time of installation. All other 396 or 427 cubic inch engine passenger cars require only proper wire routing to avoid heat damage from the manifold. This wiring should be checked for proper routing at the time of new car preparation.
PARTS AND LABOR DATA - Position and Tape Engine Wiring Harness 1968 Corvette 396 or 427 Cubic Inch Engine.
Chevrolet Motor Division
General Motors Corporation
Article ID: 943
Created: October 7, 2014
Last Updated: October 7, 2014
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article/1968-corvette-service-bulletin-heat-damage-to-engine-wiring-harness-943.html