I. Dashboard Lights:
* Bulbs: The most common cause. The 1991 Buick Regal likely uses small wedge-base bulbs (often 1.2W or similar) for the instrument panel. You'll need to:
1. Locate the bulbs: This varies depending on the specific dash design. You might need to remove the instrument cluster bezel (the plastic surround) to access the bulbs. This usually involves removing screws and carefully prying it loose. Consult a repair manual for your specific model.
2. Replace the bulbs: Carefully remove the faulty bulb(s) and replace with new ones of the same type and wattage. Make sure the new bulbs are seated correctly.
3. Reassemble: Carefully put everything back together.
* Instrument Cluster Issues: If multiple bulbs are out or the entire cluster is malfunctioning, there might be a problem with the instrument cluster itself:
1. Bad Connections: Check the connections at the back of the instrument cluster. Loose or corroded connections can interrupt power. Clean the connections with a contact cleaner.
2. Faulty Circuit Board: A more serious issue is a problem with the printed circuit board in the instrument cluster. This often requires professional repair or replacement of the cluster.
* Fuses: Check the fuses related to the instrument panel lighting. Your owner's manual will show the fuse box location and diagram.
* Dimming Switch: A faulty dimmer switch can cause the dash lights to be dim or not work at all. This usually requires replacing the switch, a job best done with a repair manual.
II. Tail Lights:
* Bulbs: Again, this is the most frequent culprit. Identify the type of bulbs (usually larger than dash bulbs) for your tail lights (brake, turn signals, reverse, etc.). Access them through the lens covers (often requires unscrewing or popping them out).
* Fuses: Check the appropriate fuses in the fuse box. Tail lights often have separate fuses for running lights, brake lights, and turn signals.
* Wiring: Damaged or corroded wiring can prevent current from reaching the bulbs. Inspect the wiring harness leading to the tail lights for any breaks, loose connections, or corrosion. Pay close attention to the connection points at the rear of the car.
* Tail Light Switch (Brake Light Switch): A faulty brake light switch prevents the brake lights from working. This is usually located near the brake pedal. Testing requires a multimeter or a helper to test brake light function.
* Ground Connection: A poor ground connection can cause erratic or non-functioning lights. Make sure the ground wire for the tail lights is clean and securely connected to the chassis.
Important Considerations:
* Repair Manual: A Haynes or Chilton repair manual for your 1991 Buick Regal is invaluable. It provides detailed diagrams and instructions for accessing components and performing repairs.
* Safety: Always disconnect the negative battery cable before working on any electrical components to avoid shocks.
* Professional Help: If you are not comfortable working with car electrical systems, it's best to take your car to a qualified mechanic.
By systematically checking these areas, you should be able to isolate the cause of your dash and tail light problems and make the necessary repairs. Remember to always replace bulbs with the correct wattage and type to avoid damage to your vehicle's electrical system.
