Overheating issues got you down? Tired of that noisy, power-robbing mechanical fan? Upgrading to an electric fan can drastically improve your vehicle's cooling efficiency, especially in stop-and-go traffic or hot climates. While there are many aftermarket electric fan kits available, a popular and cost-effective alternative is to adapt a fan and relay from a Volvo 940. These fans are known for their reliability, powerful airflow, and relatively easy integration into a variety of vehicles. This article will guide you through the process of converting your vehicle's cooling system using a Volvo 940 electric fan and relay, ensuring your engine stays cool and your wallet stays happy.
Why Choose a Volvo 940 Fan Anyway?
Okay, so you're thinking about ditching the old mechanical fan. Good choice! But why a Volvo 940 fan specifically? There are a few solid reasons:
Power and Efficiency: Volvo 940 fans are known for moving a lot of air. They're designed to cool a relatively large engine, so they're more than capable of handling many other applications. Plus, electric fans only run when needed, saving you horsepower and fuel compared to a constantly spinning mechanical fan.
Reliability: These fans are built to last. Volvo parts, in general, are known for their durability, and the 940 fan is no exception. You're likely getting a proven, robust component.
Cost-Effectiveness: Compared to some aftermarket electric fan kits, sourcing a used Volvo 940 fan and relay can be significantly cheaper. You can often find them at junkyards or online marketplaces for a reasonable price.
Availability: Volvo 940s were produced for a good number of years, so finding the necessary parts is generally not too difficult.
Gathering Your Arsenal: Parts and Tools You'll Need
Before you dive in, make sure you have everything you need. This will save you time and frustration later on. Here's a checklist:
- Volvo 940 Electric Fan: Ideally, get the fan and its shroud as a complete unit. This will make mounting easier.
- Volvo 940 Fan Relay: This is crucial for controlling the fan. Make sure you get the relay that's specifically designed for the fan.
- Wiring: You'll need a good amount of appropriately sized wiring (12-14 gauge is usually sufficient). Get both primary wire and some smaller gauge wire for the control circuit.
- Inline Fuse Holder and Fuse: Protect your electrical system! Choose a fuse amperage appropriate for the fan's current draw (usually around 30-40 amps).
- Wire Connectors: Crimp connectors, butt connectors, or solder and heat shrink tubing - choose your preferred method for making secure electrical connections.
- Wire Loom: Protect your wiring from abrasion and heat.
- Temperature Sensor/Switch (Optional): If you want the fan to automatically turn on at a specific temperature, you'll need a temperature sensor/switch that can be installed in your radiator or engine block.
- Mounting Hardware: Brackets, bolts, nuts, and washers for securing the fan shroud to your radiator.
- Tools:
- Wire strippers/crimpers
- Multimeter
- Socket set and wrenches
- Screwdrivers
- Drill and drill bits
- Pliers
- Soldering iron (optional, but recommended for secure connections)
- Heat gun (if using heat shrink tubing)
- Hacksaw or cutting wheel (for trimming the fan shroud, if necessary)
Prep Work: Getting Ready for the Conversion
Before you start tearing things apart, there are a few things you should do:
- Safety First: Disconnect the negative terminal of your battery. This is crucial to prevent electrical shocks and damage to your vehicle's electrical system.
- Inspect the Fan: Thoroughly inspect the Volvo 940 fan for any signs of damage. Check the blades for cracks, the motor for smooth operation, and the wiring for any fraying or corrosion.
- Test the Fan (Optional): Before you install the fan, you can test it by connecting it directly to a 12V power source. This will confirm that it's working properly. Be careful not to run it for too long without proper cooling, as it can overheat.
- Plan Your Mounting Strategy: Take a good look at your radiator and engine bay. Determine how you're going to mount the fan shroud. You may need to fabricate some brackets or modify the shroud to fit properly.
- Remove the Mechanical Fan: Carefully remove your existing mechanical fan. This usually involves removing the fan shroud and then unbolting the fan from the water pump pulley. Be careful not to damage the radiator fins during removal.
Wiring the Volvo 940 Fan and Relay: A Step-by-Step Guide
This is where things get a little more technical, but don't worry, we'll break it down. The Volvo 940 fan relay is the key to controlling the fan's operation.
Identify the Relay Terminals: The Volvo 940 fan relay typically has four or five terminals. Refer to the relay's wiring diagram (often printed on the relay itself) to identify each terminal. The common terminals are:
- Terminal 30: Constant 12V power (directly from the battery, through a fuse).
- Terminal 87: Output to the fan (positive wire).
- Terminal 85: Ground.
- Terminal 86: Trigger wire (switched 12V power or temperature sensor signal).
- (Optional) Terminal 87a: Normally Closed contact, not used in this application.
Connect the Power Source: Connect a heavy-gauge wire (12-14 gauge) from the positive terminal of your battery to Terminal 30 of the relay. Be sure to include an inline fuse holder with a fuse rated for the fan's amperage draw (30-40 amps is a good starting point). This provides the constant 12V power needed to operate the fan.
Connect the Fan: Connect a heavy-gauge wire from Terminal 87 of the relay to the positive wire of the Volvo 940 fan. Connect the negative wire of the fan to a good ground point on the vehicle's chassis.
Connect the Ground: Connect a wire from Terminal 85 of the relay to a good ground point on the vehicle's chassis. Make sure the ground connection is clean and secure.
Connect the Trigger Wire: This is where you have a couple of options, depending on how you want the fan to operate:
Option 1: Switched 12V Power: Connect Terminal 86 of the relay to a switched 12V power source in your vehicle's electrical system. This could be a wire that's only hot when the ignition is on. This will cause the fan to run whenever the ignition is on.
Option 2: Temperature Sensor/Switch: Connect Terminal 86 of the relay to the output of a temperature sensor/switch. The temperature sensor/switch will close the circuit when the engine reaches a certain temperature, triggering the relay and turning on the fan.
- Install the temperature sensor/switch in your radiator or engine block, following the manufacturer's instructions.
- Connect the temperature sensor/switch's power wire to a 12V power source (either switched or constant, depending on the sensor's design).
- Connect the temperature sensor/switch's output wire to Terminal 86 of the relay.
Double-Check Your Wiring: Before you reconnect the battery, carefully double-check all of your wiring connections. Make sure everything is secure and properly insulated.
Mounting the Fan: Making it Fit
This is where your ingenuity and fabrication skills might come into play. The goal is to securely mount the Volvo 940 fan and shroud to your radiator without damaging it.
Position the Fan: Place the fan and shroud in front of your radiator and determine the best mounting location. Make sure the fan blades have enough clearance from the radiator fins.
Fabricate Brackets (If Necessary): You may need to fabricate some brackets to attach the fan shroud to your radiator support. Use sturdy metal and make sure the brackets are strong enough to support the weight of the fan.
Attach the Shroud: Use bolts, nuts, and washers to securely attach the fan shroud to your radiator support. Be careful not to overtighten the bolts, as this could damage the radiator.
Trim the Shroud (If Necessary): If the fan shroud is too large, you may need to trim it to fit. Use a hacksaw or cutting wheel to carefully trim the shroud, making sure to avoid damaging the fan blades.
Testing and Troubleshooting: Making Sure Everything Works
Once you've wired and mounted the fan, it's time to test it out.
Reconnect the Battery: Reconnect the negative terminal of your battery.
Start the Engine: Start your engine and let it idle.
Monitor the Temperature: Monitor your engine's temperature gauge. If you're using a temperature sensor/switch, the fan should turn on when the engine reaches the set temperature. If you're using a switched 12V power source, the fan should turn on as soon as the ignition is on.
Check for Airflow: Make sure the fan is blowing air through the radiator.
Troubleshooting: If the fan doesn't turn on, check the following:
- Fuse: Make sure the fuse in the inline fuse holder is not blown.
- Relay: Test the relay to make sure it's working properly.
- Wiring Connections: Double-check all of your wiring connections to make sure they are secure.
- Temperature Sensor/Switch: If you're using a temperature sensor/switch, make sure it's functioning correctly.
Frequently Asked Questions (FAQ)
What fuse size should I use? Typically, a 30-40 amp fuse is sufficient for a Volvo 940 fan, but check the fan's specifications for the exact amperage draw.
Can I wire the fan to run constantly? Yes, by connecting the relay trigger wire to a constant 12V source, the fan will run whenever the battery is connected. However, this is not recommended, as it can shorten the fan's lifespan and drain your battery.
Where can I find a Volvo 940 fan? Junkyards and online marketplaces (like eBay) are good places to source used Volvo 940 fans and relays.
Do I need to use a relay? Yes, using a relay is crucial. The fan draws a significant amount of current, and wiring it directly to a switch or sensor can damage those components.
What if the fan is too big for my radiator? You may need to trim the fan shroud or fabricate custom mounting brackets to make it fit properly.
Conclusion
Converting to an electric fan using a Volvo 940 fan and relay is a worthwhile upgrade that can improve your vehicle's cooling performance and efficiency. By following these steps carefully, you can successfully install the fan and enjoy the benefits of a cooler running engine. Remember to prioritize safety and double-check your work to ensure a reliable and long-lasting installation.