1. The Obvious (and Easy):
* Fuses: Check the wiper fuse(s) in the fuse box (usually under the hood and/or inside the cabin). Consult your owner's manual to locate the correct fuse(s) for the wipers. Replace any blown fuses.
* Wiper Switch: Try wiggling the wiper stalk. A faulty connection within the switch itself can cause intermittent operation. If wiggling it seems to help, the switch is likely suspect.
* Low Washer Fluid: While it seems unrelated, some systems use the washer fluid reservoir's level sensor to trigger a low-fluid warning, which may also disable or intermittently activate the wipers in some models.
2. More Involved Checks:
* Wiper Motor: This is a more complex issue. You can test the motor directly (often requires removing some parts for access), but doing this safely usually means disconnecting the battery negative terminal before proceeding. If the motor runs strongly when tested directly (with battery positive to the motor's positive and negative to the motor's negative - carefully!), then the problem is likely elsewhere (wiring, switch, etc.). A weak or failing motor will often struggle or run intermittently.
* Wiper Motor Connector: Check the connector that plugs into the wiper motor for corrosion or loose connections. Clean or repair as needed.
* Wiring and Connections: Trace the wiring from the wiper switch to the motor. Look for any breaks, corrosion, or loose connections along the way. This might require some careful probing with a multimeter to check for continuity.
* Wiper Linkage: Inspect the linkage connecting the motor to the wipers. A stiff or broken linkage can cause the wipers to move erratically.
* Ground Connections: Poor ground connections can cause all sorts of electrical gremlins. Ensure that the ground connections for the wiper motor and switch are clean and secure.
* Multi-Function Switch (Wiper Switch): As mentioned above, if wiggling the switch doesn't resolve the issue, the multi-function switch itself may be failing internally. Replacing this part is often more involved but is frequently the culprit.
* Computer Module (PCM/BCM): In some cases, a faulty body control module (BCM) or powertrain control module (PCM) can cause intermittent wiper issues. This is a more advanced diagnosis that typically requires a professional scan tool to verify.
3. Getting Help:
* Owner's Manual: This is your first resource. It should provide details on fuse locations and troubleshooting tips.
* Online Forums: Search for forums related to your specific 1998 Chevy Silverado. Other owners may have experienced similar problems and posted solutions.
* Auto Parts Store: Auto parts stores can often test your wiper motor and switch. They can also help you identify and source replacement parts.
* Mechanic: If you're not comfortable working on your vehicle yourself, a qualified mechanic can diagnose and repair the problem.
Remember safety first! Disconnect the battery's negative terminal before working directly with electrical components. Start with the simple checks before moving on to more involved troubleshooting.
