* Burnt-out Bulbs: The most common cause. Check all the rear turn signal bulbs (left and right). A single burnt-out bulb can sometimes cause the entire side's turn signals to malfunction, while the hazard lights (which use a separate circuit) still work.
* Faulty Turn Signal Switch: The switch itself might be failing. It's responsible for directing power to the correct side's turn signals. If it's failing, it might not send power to the turn signals but still allow the hazard lights to operate.
* Wiring Issues: A break, short, or corrosion in the wiring for the turn signals (but not the hazards) is a possibility. This could be anywhere between the switch and the taillights. Look closely at the wiring harness near the taillights for damage.
* Turn Signal Flasher: While less likely, a faulty flasher unit could be at fault. The flasher is responsible for the blinking action. A bad flasher could prevent the turn signals from working but leave the hazards (which often have a separate flasher) functional. Many Blazers of that era used two flashers, one for hazards, and one for turn signals.
* Multi-Function Switch (Turn Signal Switch): The switch that controls your turn signals, headlights, windshield wipers, etc., is sometimes called a multi-function switch. This switch is a common failure point and a likely suspect.
* Fuse: Check the fuse box for any blown fuses related to the turn signals. It's possible a fuse related to only the turn signals is blown.
Troubleshooting Steps:
1. Check the Bulbs: This is the easiest and quickest check. Replace any burnt-out bulbs.
2. Check the Fuses: Look for blown fuses associated with the turn signals. The owner's manual will show you which fuses are responsible for the turn signal system.
3. Inspect the Wiring: Look for any obvious damage, corrosion, or breaks in the wiring harness, particularly near the taillights and the multi-function switch.
4. Test the Flasher: If the bulbs and fuses are good, you might need to test the turn signal flasher (and potentially the hazard flasher, to ensure it is operating properly).
5. Test the Multi-Function Switch: This is best done by a qualified mechanic, as testing this component requires specialized tools and knowledge.
If you're not comfortable working with car electrical systems, it's best to take your Blazer to a qualified mechanic for diagnosis and repair. Improper wiring can lead to further damage or even safety hazards.
