1. Check the Signal Light Switch:
- Locate the signal light switch on the steering column.
- Turn the ignition switch ON.
- Move the lever up or down to signal.
- If the signal light switch does not return to the center position, it may be faulty and need replacement.
2. Check the Turn Signal Flasher:
-Turn OFF the ignition.
-Locate the turn signal flasher, which is usually under the dash near the steering column.
-Remove the flasher by gently pulling it out of its socket.
-Inspect the flasher for any damage or corrosion.
-Replace the flasher if it appears damaged.
3. Inspect the Signal Light Wiring:
- Turn ON the ignition and hazard lights.
- Follow the signal light wiring harness from the turn signal switch to the signal lights.
- Wiggle the wiring to check if a loose connection is causing the problem.
- Repair any loose connections or damaged wiring.
4. Check the Signal Light Bulbs:
- Open the light sockets and check that the bulbs are properly seated.
- Replace any burned out or faulty signal light bulbs.
5. Check Light Socket:
- Corroded sockets can sometimes interfere with the signal lights.
- Remove the light bulbs and check for corrosion.
- Clean the sockets with a wire brush or electrical contact cleaner.
6. Test Signal Light Circuit:
- With the ignition ON, use a multimeter to check if the turn signal circuit is getting power.
- Follow the wiring diagram to locate the appropriate wires.
- If there is no power, the problem may be in the wiring or switch.
7. Check the Turn Signal Control Module:
-If your 1990 Buick Lesabre has a turn signal control module (TSM), it may be the cause of the signal lights not working.
- The TSM usually located under the dash.
- Check for any loose or disconnected connections.
- Replace the TSM if it appears damaged.
