* Worn-out wiper motor: This is the most common cause. The motor itself might be failing, or the brushes inside are worn down, preventing it from functioning at any speed.
* Faulty wiper motor switch: The switch on the steering column controls the wiper speed and function. A broken switch can prevent any power from reaching the motor.
* Blown fuse: Check your owner's manual to locate the fuse for the wipers and test it with a multimeter. A blown fuse is a relatively easy and inexpensive fix.
* Bad wiper switch relay: Relays act as electrical switches, controlled by the switch on the steering column. A faulty relay can prevent power from getting to the motor.
* Wiring problems: Corrosion, broken wires, or loose connections in the wiring harness leading to the motor or switch can interrupt the electrical circuit. This is particularly common in older vehicles due to age and exposure to the elements.
* Multi-function switch (turn signal/wiper switch): This is a single unit that controls turn signals, wipers, and sometimes headlight functions. A fault in this component can affect all aspects.
* Ground issue: A poor ground connection can prevent the motor from receiving the proper amount of power.
* Park/Neutral Position Switch (PNPS) issue (less likely, but possible): On some vehicles the wiper function is disabled unless the vehicle is in Park or Neutral. If your PNPS is faulty, it could prevent the wipers from operating regardless of the selected setting.
Troubleshooting Steps:
1. Check the fuses: This is the easiest and cheapest first step.
2. Inspect the wiper motor: Listen for any clicking sounds when you try to activate the wipers. A clicking noise could indicate a problem with the motor itself or a lack of power.
3. Test the wiper switch: See if the wipers work on other speeds. If only the intermittent function is failing, the problem is likely isolated to that specific setting.
4. Check the wiring: Look for any visible damage to the wiring harness.
5. Use a multimeter: This is crucial for checking voltage and continuity of the circuits and components. You'll need to refer to a wiring diagram specific to your 1998 Chevy Tahoe.
If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Incorrectly diagnosing and repairing electrical issues can lead to further damage.
