* Hazard switch: The most frequent cause. The hazard switch might be stuck or malfunctioning, sending power to both sides simultaneously, regardless of which turn signal is activated. Try turning the hazard lights off and on several times to see if it resolves the issue. If the problem persists, the hazard switch itself may need replacing.
* Turn signal switch (stalk): The switch on the steering column that activates the turn signals could be faulty. Internal contacts may be worn or shorting out. This is a more complex repair usually requiring professional diagnosis and replacement.
* Wiring issue: A short circuit or damaged wire in the turn signal circuit is another possibility. This could be anywhere from the switch to the bulbs, including within the wiring harness. This is usually the most difficult issue to diagnose and repair, often requiring tracing the wiring.
* Ground fault: A poor ground connection can cause erratic electrical behavior, including this symptom.
* Multi-function switch (some models): Some Chevy trucks from this era use a multi-function switch that controls the turn signals, wipers, and other functions. A faulty multi-function switch could be the source of the problem.
Troubleshooting Steps:
1. Check the hazard switch: As mentioned above, this is the easiest check.
2. Check the bulbs: Make sure all your turn signal bulbs are working correctly. A burned-out bulb on one side *can* sometimes cause this issue, though it's less common than the switch problems.
3. Visual inspection: Carefully inspect the wiring harness for any visible damage, cuts, or loose connections, particularly near the steering column and the taillights.
4. Test the turn signal relay (if accessible): The relay acts as a switch for the turn signals. A faulty relay can cause problems. Accessing and testing this may require some mechanical knowledge. (Consult a repair manual for your specific model.)
If you're not comfortable working on your vehicle's electrical system yourself, it's best to take it to a qualified mechanic. They have the tools and experience to diagnose and repair the problem accurately and safely. Providing them with the information that both sides blink when you engage the *right* turn signal will help them narrow down the possibilities.
