1965 Corvette: Service Bulletin: Turn Signal Switch - Failure to Cancel

Subject: Turn Signal Switch - Failure to Cancel
Model and Year: 1965 Vehicles - All Models Except Chevelle
Source: Chevrolet Technical Service Bulletin
Bulletin Number:  DR #706, Section XII
Date:   October 26, 1964

TO:  ALL CHEVROLET DEALERS

Early production 1965 vehicles, except Chevelle, may exhibit a "failure to cancel" or a "partial cancel" condition of the turn signal switch assembly.  This condition is prevalent from the right turn position and caused by a number of variables within the switch assembly.  The cancelling cams are not the cause of the malfunction.

A complete failure to cancel is obvious but when partial cancel occurs, the turn signal lights will go out but one brake light will be inoperative.  This could easily be incorrectly diagnosed as a bulb, socket, or wiring failure.

If this problem is encountered, follow the procedure outlined on page 2 of this bulletin.

It should also be noted that if for any reason the actuator lever is removed from the switch body, the "O" ring must be placed in the body cavity (as shown on the attached sketch) when reinstalling the lever.  The correct horn wire routing is also illustrated in the sketch.

Service Procedure

1. Remove steering wheel (refer to Section 9 of Shop Manual).
2. Remove and discard both rubber bumpers from the actuating plate (see sketch).
3. Using a small file, such as an ignition point file, open the gap in the cancelling pawls to .055/.060 (rework both sides).  NOTE:  After cleaning any flash from the moveable arm face, perform the stock removal from the stationary arm.
4. Blow out loose filings with air hose.
5. Replace the steering wheel, temporarily, and test the switch for cancelling.
6. If the switch now works correctly, reinstall the steering wheel.  If the switch still fails to cancel, it will be necessary to replace the switch assembly (Part No. 910821).