* Thermostatically controlled switch: This is the most common method. A temperature sensor (often located in the radiator or engine block) monitors coolant temperature. When the coolant reaches a certain temperature (typically around 212°F/100°C), this switch closes, completing a circuit and sending power to the fan motor. When the temperature drops, the switch opens, turning the fan off. This is usually a single-speed fan.
* Computer controlled (PCM): The Powertrain Control Module (PCM) can also control the cooling fan. This allows for more sophisticated control, such as multiple fan speeds or operation based on factors beyond coolant temperature (like air conditioning demand). This is more common on later-model cars but *could* be present in some 1993 models, depending on the specific options and trim level.
Troubleshooting:
If your fan isn't working, here's a basic troubleshooting sequence:
1. Check the fan directly: With the engine hot, jump power directly to the fan motor to see if it runs. If it does, the problem lies in the wiring, the temperature switch, or the PCM. If it doesn't, the fan motor itself is likely faulty. Caution: Always be careful when working around hot engine components.
2. Check the fuse: Inspect the fuse for the cooling fan in the fuse box. A blown fuse is an easy fix.
3. Check the relay: Many cooling fan systems use a relay to switch the high current needed for the fan motor. A bad relay can prevent the fan from working. You'll need to check your vehicle's wiring diagram to locate the relay.
4. Check the temperature switch: This might require testing the switch with a multimeter to see if it's closing at the correct temperature. You'll need to consult a wiring diagram to find the location and specifications of the switch.
5. Consult a wiring diagram: A factory service manual or a reliable online resource with wiring diagrams for your specific year and model Dodge Shadow is essential for more advanced troubleshooting. This will help you trace the wiring, identify the relay, and test the various components.
If you're not comfortable working with automotive electrical systems, it's best to take your vehicle to a qualified mechanic. Improper electrical work can lead to damage to your vehicle.
