1. Check the Fan's Fuse(s):
* Location: Consult your owner's manual to find the location of the fuse(s) for the cooling fan. There might be separate fuses for high and low speed, or a single fuse for both.
* Check for Blown Fuse: Visually inspect the fuse(s). A blown fuse will have a broken filament (wire) inside. Replace any blown fuses with the correct amperage rating.
2. Check the Fan Relay(s):
* Location: The relay(s) are usually located in a fuse box (under the hood or inside the car). Again, your owner's manual is crucial. There might be multiple relays, one for high speed and another for low speed, or just one.
* Visual Inspection: Look for any obvious damage to the relay.
* Testing the Relay (Requires Multimeter): This is the most effective way to check a relay. You need a multimeter to check for continuity. Many online tutorials show how to test relays. The method varies slightly depending on the type of relay. Swapping a known good relay with the suspect one is a quicker test if you have a spare.
3. Check the Coolant Temperature Sensor (CTS):
* Location: The CTS is usually located in the engine block or cylinder head. Its location varies depending on the engine type. Consult a repair manual or online diagrams for your specific Beretta engine.
* Testing the CTS (Requires Multimeter): A faulty CTS can prevent the fan from turning on because it doesn't signal the ECU (Engine Control Unit) that the coolant is overheating. Testing involves checking resistance values at various temperatures. Online resources provide the correct resistance values for your specific CTS. Often, simply disconnecting the sensor and jumping the wires will force the fan on (only do this for testing purposes, and turn off the engine immediately afterwards).
4. Check the Engine Control Unit (ECU):
* This is the most difficult to test yourself. A malfunctioning ECU can cause various problems, including a non-functional cooling fan. ECU testing often requires specialized tools and knowledge. This is best left to a qualified mechanic.
5. Check the Fan Motor Itself:
* Testing the Fan Motor (Requires Multimeter or 12V Power Source): Disconnect the fan motor's connector and apply 12V directly to the motor's terminals (using a jumper wire attached to the battery with caution). If the motor spins, the problem is likely elsewhere in the circuit. If it doesn't spin, the motor is faulty and needs replacement.
6. Wiring Harness Issues:
* Inspect the wiring harness leading to the fan motor, relay, and CTS for any damaged wires, loose connections, corrosion, or broken connectors. Repair or replace as needed.
Important Notes:
* Safety First: Work on your car only in a safe and well-ventilated area. Always disconnect the negative battery terminal before working on the electrical system.
* Repair Manual: A repair manual specific to your 1991 Chevy Beretta is invaluable. It will provide detailed diagrams and specifications.
* Professional Help: If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic. Overheating can cause serious engine damage.
By systematically checking these components, you should be able to pinpoint the cause of your cooling fan problem. Remember to replace parts with the correct specifications.
