1. The Wiper Switch:
* Test: Try all wiper speeds. If *all* speeds are intermittent or erratic, the switch itself is a prime suspect. A faulty switch might have internal corrosion or worn contacts.
* Repair: Replacing the wiper switch is often the solution. It's relatively easy to replace, but requires some mechanical aptitude. You'll need to locate the switch (usually under the steering column or dash), disconnect the electrical connectors, and install the new switch. Consult a repair manual specific to your 1999 Buick Regal for detailed instructions.
2. The Wiper Motor:
* Test: Listen carefully for unusual noises (grinding, clicking) from the motor when you activate the wipers. If the motor runs intermittently or not at all, it could be failing. Also check the motor's linkage – make sure it's properly connected and moves freely.
* Repair: Replacing the wiper motor is more involved, often requiring removal of the wiper arms and cowl. Again, a repair manual is essential. Sometimes, cleaning and lubricating the motor's mechanism can resolve minor issues.
3. The Wiper Control Module (or Relay):
* Test: This is trickier to test without a multimeter and knowledge of the car's electrical system. The control module (or relay) acts as the brain, controlling the intermittent timing. A faulty module can cause unpredictable wiping patterns.
* Repair: Replacement is the usual solution. Locating this component may require some investigation – consult your repair manual for its location.
4. Wiring and Connectors:
* Test: Inspect the wiring harness leading to the wiper motor, switch, and control module for any damaged, frayed, or corroded wires. Pay close attention to connectors; they can become loose or corroded.
* Repair: Repair or replace any damaged wiring. Clean corroded connectors with contact cleaner.
5. Multi-Function Switch (if applicable):
* Test: Some models incorporate the wiper control into a larger multi-function switch controlling lights, turn signals, etc. If other functions are acting strangely, the switch itself might be the problem.
* Repair: Similar to the wiper switch, this requires replacement and consultation of a repair manual.
6. Ground Connections:
* Test: Poor ground connections can disrupt the electrical signal to the wiper motor. Check all grounding points related to the wiper system for corrosion and secure connections. Clean and tighten as needed.
Troubleshooting Steps:
1. Start with the simplest: Check the wiper switch and fuses first.
2. Listen carefully: Unusual noises from the motor often indicate a mechanical problem.
3. Visual inspection: Look for obvious signs of damage in the wiring and connectors.
4. Consult a repair manual: This is crucial for locating components, understanding the wiring diagram, and following proper repair procedures. A Haynes or Chilton manual is a good investment for DIY repairs.
5. Consider professional help: If you're not comfortable with electrical work or car repairs, take your Buick to a qualified mechanic. Misdiagnosis can lead to unnecessary parts replacement.
Remember safety first! Disconnect the negative battery terminal before working on any electrical components. Always refer to a repair manual specific to your 1999 Buick Regal for detailed instructions and diagrams.
