FOUR SEASONS 956JZ20 Engine Cooling Fan Controller B-200

( Brand: Four Seasons ), ( Manufacturer Part Number: 956JZ20 ), ( Part Type: Fan Engine Controller ), ( Manufacturer Warranty: 1 Year ), ( Bundle: No ), ( Cs-sku: 328 )

Review FOUR SEASONS Ford Engine Cooling Fan Controller fits 1985–1991

The **Seasons 956JZ20** is a high-performance, precision-engineered cooling fan controller designed specifically for the **1985 1991 Ford B-Series (E-150, E-250, E-350, and Super Duty) engines equipped with the iconic 7.5L (454 cubic inch) V8**, particularly those featuring the **B-200** cooling system. This advanced electronic controller replaces the stock mechanical or vacuum-operated fan clutch, offering superior cooling efficiency, reduced wear on the engine, and enhanced reliability under demanding conditions. Built with a robust **solid-state relay** and a **temperature-sensitive thermistor**, the 956JZ20 provides seamless, variable-speed fan operation that adjusts dynamically to the engine s cooling needs, ensuring optimal performance whether cruising on the highway, towing heavy loads, or operating under extreme heat. The controller features a **dual-stage cooling system**, allowing the fan to run at a lower speed during normal operating temperatures while ramping up to full capacity when the engine approaches critical heat levels, thereby extending the life of the fan motor and reducing electrical strain. Its **waterproof and vibration-resistant** design ensures durability in harsh environments, making it ideal for commercial, industrial, and heavy-duty applications where reliability is paramount. Installation is straightforward, requiring only basic wiring connections to the existing cooling fan circuit, and the unit includes a **pre-wired harness** for easy compatibility with the Ford B-Series electrical system. Whether used in a classic muscle truck, a workhorse pickup, or a high-performance towing rig, the Seasons 956JZ20 delivers **superior cooling control**, reducing fan cycling, minimizing wear, and helping maintain peak engine performance across all operating conditions.

The **956JZ20** is a popular aftermarket cooling fan controller designed for **1985 1991 Ford B-Series trucks and vans** with the **302/351W/460/500/7.5L/8.0L** engines. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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### **Pros of the 956JZ20 Fan Controller**

1. **Improved Cooling Efficiency**

The 956JZ20 is a **temperature-sensitive fan controller**, meaning it activates the cooling fan based on engine temperature rather than relying solely on the vehicle s stock thermostat or electrical switch. This ensures the fan turns on when the engine is hot enough but not unnecessarily early, improving cooling efficiency and reducing wear on the fan motor.

2. **Reduces Fan Cycling Stress**

Stock cooling fans often run continuously or cycle on/off abruptly, which can cause excessive strain on the fan motor and belts. The 956JZ20 provides **smoother, more controlled fan engagement**, extending the life of the fan and associated components.

3. **Compatibility with Aftermarket Fans**

Many modern or high-performance cooling fans (e.g., **Duro, ACDelco, or performance-grade fans**) require a controller to operate correctly. The 956JZ20 is designed to work with **12V electric fans**, making it a versatile choice for upgrades.

4. **Adjustable Temperature Settings**

Some versions of the 956JZ20 allow for **temperature adjustment** (via potentiometer or wiring modifications), letting you fine-tune when the fan activates. This is useful for **high-performance builds** where cooling demands differ from stock setups.

5. **Easy Installation**

The unit is relatively straightforward to install, typically requiring only basic wiring connections to the existing cooling fan circuit. No major modifications to the engine bay are usually needed.

6. **Cost-Effective Upgrade**

Compared to a full cooling system overhaul, the 956JZ20 is an **affordable solution** for improving fan operation without replacing the entire cooling setup.

7. **Reduces Electrical Load on Alternator**

Since the fan runs only when necessary (rather than continuously), it **lowers the electrical demand** on the alternator, which can be beneficial for older vehicles with weaker charging systems.

8. **Works with Stock or Upgraded Cooling Systems**

Whether you have a **stock radiator, aftermarket radiator, or a performance cooling package**, the 956JZ20 can integrate seamlessly.

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### **Cons of the 956JZ20 Fan Controller**

1. **Limited to Electric Fans**

The 956JZ20 **only works with 12V electric cooling fans**. If your vehicle originally had a **mechanical (thermostat-driven) fan**, you ll need to upgrade to an electric fan first, adding to the cost.

2. **Potential for False Triggers**

In some cases, **excessive electrical noise, loose wiring, or a failing thermostat** can cause the controller to misinterpret temperature readings, leading to **unexpected fan activation**. Proper installation and grounding are crucial.

3. **No Built-In Overload Protection**

Unlike some modern controllers, the 956JZ20 **does not include built-in overload protection** for the fan motor. If the fan motor fails or gets stuck, it could **draw excessive current**, potentially damaging wiring or fuses.

4. **Temperature Sensitivity Can Be Inconsistent**

Some users report that the **temperature threshold for fan activation isn t perfectly consistent**, especially in extreme heat or cold. Adjustments may be needed for optimal performance.

5. **Not Ideal for Extreme Performance Applications**

For **high-RPM, forced induction, or extreme towing applications**, a **more advanced controller (e.g., with dual-stage or programmable settings)** may be necessary to handle higher cooling demands.

6. **Requires Proper Wiring and Grounding**

Poor installation such as **weak grounding, thin wiring, or improper fuse placement** can lead to **intermittent fan operation or electrical issues**. This may require additional wiring work beyond the controller itself.

7. **No LED or Diagnostic Indicators**

Unlike some newer controllers, the 956JZ20 **does not include an LED or diagnostic features** to confirm proper operation. You ll need to rely on **visual and audible checks** to ensure the fan is engaging correctly.

8. **Compatibility with Some Aftermarket Fans May Vary**

While it works with most **12V electric fans**, **high-performance or dual-stage fans** might require additional modifications or a different controller for optimal performance.

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### **Conclusion**

The **956JZ20 is a solid, budget-friendly choice** for improving cooling fan operation in **1985 1991 Ford B-Series trucks and vans**, particularly if you re upgrading to an **electric cooling fan**. It offers **better temperature-sensitive control, reduced fan cycling stress, and improved efficiency** compared to stock setups. However, it has **limitations in extreme applications** and requires **proper installation** to avoid issues.

If your primary goal is **reliable, basic fan control** and you re not pushing the engine to extreme limits, the 956JZ20 is a **good, cost-effective solution**. For **high-performance builds, dual-stage cooling, or advanced diagnostics**, a more sophisticated controller may be worth the investment.

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### **Recommendation**

- You re upgrading to an **electric cooling fan** and want **better temperature-based control**.

- Your vehicle is used for **mild to moderate duty** (daily driving, light hauling).

- You re on a **budget** and need a simple, effective upgrade.

- You re comfortable with **basic wiring and troubleshooting**.

- You have a **high-performance engine** (turbocharged, supercharged, or extreme towing).

- You want **dual-stage cooling** (low-speed and high-speed fan operation).

- You prefer a **controller with diagnostic features** (e.g., LED indicators).

- Your installation involves **complex wiring or multiple fans**.

For most **stock-to-moderate-upgrade scenarios**, the **956JZ20 is a reliable and practical choice**. Just ensure **proper installation, good grounding, and compatible fan selection** for the best results.

Details:

Consequently, the picture displayed may not always reflect most recent changes, though this occurs rarely. They may even discontinue an item and replace it with updated version. Item Specifics: Activation Control: Adjustable, Amperage Rating: 25,: Electric Fans And Accessories, Material: Plastic, Number of Terminals: 6, Style: Fan Controller, Terminal Type: Spade / Wire Lead, Accessory, voltage : 12. We source our pictures directly from the manufacturer and may not immediately receive updated photos if changes are made.

Brand: Four Seasons, Warranty: 12 Month Warranty, Part Type: Engine Cooling Fan Controller.

part #: 956jz20 prices

• $49.58-$104.51

specifications ocoosys:

• for makes: Ford
• for years: 1985-1991
• brand: Four Seasons
• mpn: 956jz20
• part type: Fan Engine Controller
• manufacturer warranty: 1 Year
• bundle: No
• cs-sku: 328

general ocoosys:

• Car Truck Parts Accessories > Engine Cooling Components > Other Engine Cooling Components
• condition: New

offer ocoosys:

• quantity: 1
• started: April 27, 2026
• options: Ship-to-home
• sold: 0
• availability: In Stock

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• cost: $0.00
• service: Standard

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seller ocoosys:

• rating: 99.7%
• city: Hempstead, New York
• # reviews: 51400

returns ocoosys:

• paid by: Seller
• policy: Returns Accepted
• time: 30 Days

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