C1 Corvette Turn Signal Problems
Problem: While driving, either the left or right brake light will not function.
This is a common problem with C! Corvettes. It is caused by failure of the turn signal canceling mechanism to re-center properly after completing a turn while using the turn signals. The canceling mechanism connects to the turn signal lever pivots, and drives a sliding pin that protrudes from the turn signal switch, and if the system doesn’t self-center properly after a turn, that pin ends up slightly off-center, which leaves the internal connection open inside the switch that feeds the bright filament on the side in the direction of the turn, and you have no brake light on that side.
The brake light switch (on the pedal arm) feeds power to the turn signal switch when you step on the brakes. If you’re driving straight down the road and the turn signal switch is centered, the turn signal switch sends that power to both tail lamp bright filaments for brake lights.
If you have the right turn signal engaged, the switch disconnects the right side bright filament wire from the brake light switch feed and connects it to the feed from the turn signal flasher so the right side bright filament only responds to the turn signal. When you complete the turn and the steering wheel returns to the straight-ahead position, the switch re-centers, disconnecting that contact from the turn signal feed and reconnects it to the brake light switch feed. “Jiggling” the lever will usually re-center the switch if it doesn’t do so by itself. This mechanism and its springs, cams, levers, pivots, and sliding surfaces collect all manner of dirt, dust, and crud over the years through the gap between the bowl and the steering wheel hub, and eventually it needs cleaning.
Cure: The cure is to remove the steering wheel, turn signal lever, and pivot screw, remove the canceling mechanism, and clean it up and lubricate all the moving parts with lubilate® including the two riveted posts in the bowl the ring slides against on the inboard side. You can also check the freedom of motion of the pin protruding from the switch itself and make sure it slides freely. Then reinstall the canceling mechanism, pivot screw and turn signal lever, and the steering wheel. Note that there is a chiseled index mark on the end of the steering shaft (which is at the 12 o’clock position with the front wheels straight ahead), and there’s another one on the steering wheel hub. Those two marks must be aligned when you reinstall the steering wheel in its correct orientation. That will locate the two canceling pins on the forward side of the wheel hum in the 8 and 10 o’clock positions as viewed from the driver’s seat, to ensure proper turn signal cancellation after a turn; there’s only ONE correct position for the steering wheel on the shaft.
This job takes only an hour of so, and will ensure that both your brake lights and turn signals work properly for many years to come.