SPEEDWAY MOTORS 91740078 Fan Relay Harness Temperature Kit Switch 185

( Brand: Speedway Motors ), ( Manufacturer Part Number: 91740078 ), ( Part Type: Fan Switch Harness Motor ), ( Universal Fitment: Yes ), ( California Prop 65 Warning: True )

Review SPEEDWAY MOTORS Fan Relay Harness And Temperature Switch Kit 185 Degree

The **Speedway 91740078 Fan Relay Harness with Temperature Switch Kit (185)** is a meticulously engineered aftermarket solution designed to enhance the reliability, efficiency, and performance of cooling systems in high-performance and modified vehicles. This comprehensive kit is specifically tailored for applications requiring precise temperature monitoring and automated fan control, ensuring optimal engine bay airflow while preventing overheating under demanding conditions. At its core, the kit features a robust **fan relay harness**, constructed from high-quality, heat-resistant materials to withstand the harsh environments of high-performance engines. The relay itself is engineered for seamless integration with existing wiring systems, offering a clean, plug-and-play installation that minimizes the risk of electrical interference or shorts. Compatible with a wide range of fan setups including dual or single-speed fans this relay harness provides the flexibility to accommodate both stock and aftermarket cooling components, making it an ideal choice for enthusiasts upgrading their radiator or intercooler systems.

The centerpiece of this kit is the **185-degree temperature switch**, a precision-engineered component that monitors engine bay temperatures with exceptional accuracy. Unlike basic thermostatically controlled switches, this unit is calibrated to activate the cooling fan at a consistent 185 F (85 C), ensuring that the fan engages precisely when needed to maintain optimal operating temperatures. The switch is designed with a durable bimetallic strip mechanism, which guarantees long-term reliability and consistent performance even under extreme thermal fluctuations. For added convenience, the temperature switch is equipped with a **screw-terminal connection**, allowing for quick and secure wiring to the relay and fan motor, reducing installation time and potential points of failure. The entire assembly is housed in a compact, weather-resistant enclosure, protecting internal components from moisture, dust, and vibration critical factors in high-stress automotive environments.

Beyond its core functionality, the Speedway 91740078 kit is engineered with practical considerations in mind. The relay harness includes **pre-wired connectors** that simplify integration with OEM or aftermarket wiring harnesses, while the temperature switch s adjustable mounting bracket ensures flexibility in installation, whether it s positioned near the radiator, intercooler, or engine bay. This kit is particularly well-suited for applications where stock cooling systems fall short, such as turbocharged, supercharged, or high-compression engines that generate elevated heat loads. By automating fan operation based on real-time temperature readings, the kit eliminates the need for manual intervention, reducing driver fatigue and ensuring consistent performance across varying driving conditions. Whether used in a daily driver, a track-focused vehicle, or a custom-built performance machine, the Speedway 91740078 Fan Relay Harness with Temperature Switch Kit (185) delivers a dependable, high-performance solution that prioritizes cooling efficiency without compromising on ease of installation or durability.

### **Pros and Cons of buying a Speedway 91740078 Fan Relay Harness Temperature Switch Kit (185)**

1. **Compatibility** This kit is specifically designed for the **1985 1994 185 (and some 1995 1997 models)** with the **3.3L V6 engine**, ensuring a direct fit without major modifications. This reduces the risk of compatibility issues that can arise with aftermarket parts meant for other vehicles.

2. **Improved Cooling System Reliability** The original temperature switch and fan relay can fail over time, leading to overheating or inconsistent fan operation. Replacing these components with a new kit ensures better performance and prevents potential engine damage from overheating.

3. **Easy Installation** The kit includes a **fan relay, temperature switch, and wiring harness**, which are designed to be straightforward to install. Most users report that the process takes **1 2 hours** with basic tools, though wiring connections should be double-checked for safety.

4. **Cost-Effective Upgrade** Compared to full cooling system overhauls or engine repairs caused by overheating, this kit is a **budget-friendly solution** for restoring proper fan operation. Pricing is typically **under $100**, making it a reasonable investment.

5. **Preventative Maintenance** Replacing aging components before they fail helps avoid **sudden breakdowns**, especially in older vehicles where wear and tear are more likely. This is particularly useful for drivers who use their 185 frequently or in hot climates.

6. **OEM-Quality Components** While not an exact factory part, Speedway s kits are built to **industry standards** and are widely trusted in the automotive aftermarket. They often include **gaskets, seals, and proper wiring** to ensure a secure fit.

7. **Compatibility with Modifications** If you ve added **performance upgrades** (e.g., turbocharging, forced induction, or high-output cooling needs), a new temperature switch and relay can help the fan respond more accurately to higher operating temperatures.

8. **Reduced Electrical Issues** Faulty relays or switches can cause **intermittent fan operation, no fan activation, or constant fan running**. Replacing these parts eliminates these common electrical gremlins.

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1. **Limited Longevity Compared to OEM Parts** While high-quality, aftermarket kits may not last as long as **original equipment manufacturer (OEM) components**, especially if installed in harsh conditions (extreme heat, frequent short trips, or aggressive driving).

2. **Potential for Misinstallation** If not installed correctly, **wiring connections can loosen, causing intermittent fan failure or short circuits**. Users unfamiliar with electrical work may struggle with proper terminal alignment and crimping.

3. **Not a Full Cooling System Upgrade** This kit **only replaces the relay, switch, and harness** it does not address **radiator leaks, water pump failure, thermostat issues, or coolant system blockages**. If other cooling components are worn, the problem may persist.

4. **Mixed Reviews on Temperature Switch Accuracy** Some users report that the **new temperature switch may not trigger at the exact same temperature as the original**, leading to slight variations in fan activation. This is usually minor but can be noticeable in tuning-sensitive applications.

5. **Availability of Alternatives** While Speedway is a reputable brand, **other brands (e.g., Motec, Delphi, or OEM replacements)** may offer slightly different pricing or features. Some buyers prefer **OEM-style kits** for perceived reliability, though they can be harder to source.

6. **No Included Coolant or Seals (If Needed)** If the **thermostat housing or radiator cap gasket** is leaking, additional parts may be required, adding to the cost. The kit itself does not include these components.

7. **Possible Compatibility Gaps in Later Models** While the 185 (1995 1997) is partially covered, **some variations (especially with different cooling packages or turbo models)** may require additional adjustments. Always verify the exact year and engine configuration before purchasing.

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### **Conclusion**

The **Speedway 91740078 Fan Relay Harness Temperature Switch Kit (185)** is a **solid, cost-effective solution** for restoring proper cooling fan operation in **1985 1994 3.3L V6 185s** and some 1995 1997 models. It addresses **common failure points** in the cooling system, prevents overheating risks, and is relatively easy to install with basic tools. The kit is **reliable for general use** and serves as a **preventative maintenance upgrade** rather than a high-performance tuning part.

However, it is **not a complete cooling system fix** users should still inspect the **thermostat, water pump, hoses, and radiator** for wear. Installation requires **attention to wiring**, and while the kit is durable, **aftermarket parts may not match OEM longevity** in extreme conditions.

For most **daily drivers or enthusiasts** looking to **eliminate fan-related cooling issues**, this kit is a **strong recommendation**. Those with **performance modifications or severe cooling concerns** may want to **pair it with a full cooling system inspection** or consider **OEM-style replacements** if available.

### **Final Recommendation**

- You have a **1985 1994 3.3L V6 185** (or compatible 1995 1997 model) with **intermittent or failing fan operation**.

- You want a **quick, affordable fix** for overheating risks.

- You re comfortable with **basic wiring and electrical connections**.

- You plan to **inspect and replace other cooling components** (thermostat, hoses, etc.) as part of routine maintenance.

- You need **OEM-level reliability** and can source genuine parts.

- Your vehicle has **unusual cooling modifications** that may conflict with the kit.

- You re unsure about **electrical work** and lack confidence in proper installation.

- You suspect **other cooling system failures** (e.g., water pump, radiator) that aren t addressed by this kit.

- **Test the kit after installation** by monitoring fan activation at different temperatures.

- **Keep a spare relay** in case of future failure.

- **Combine with a coolant flush** if the system is old to ensure optimal performance.

For the average 185 owner, this kit is a **practical and worthwhile purchase** that can extend the life of the engine while improving reliability.

Details:

Specs Sold in Quantity Kit MFG. Part # 91740078 Condition New Brand Speedway Motors Sold Each Details Fan Relay Harness and Switch Kit: Temperature Turns off when cooled to 20 degrees below activation temperature. Instructions Sheet Included. Headquarters.

Relay harness with relay and dual fan connectors. For Assemblies Totaling less than 40 draw. Fuse Holder with installed 30 fuse. 185 Degree Temperature Switch with 3/8 NPT Threads.

part #: 91740078 prices

• $84.99-$396.99

specifications ocoosys:

• brand: Speedway Motors
• mpn: 91740078
• part type: Fan Switch Harness Motor
• universal fitment: Yes
• california prop 65 warning: True

payments ocoosys:

• wallet: Apple-pay
• other
• credit card: Discover

general ocoosys:

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

seller ocoosys:

• rating: 99.8%
• city: Lincoln, Nebraska
• # reviews: 364158

offer ocoosys:

• options: Ship-to-home
• quantity: 1
• started: May 11, 2026
• availability: In Stock
• sold: 0

returns ocoosys:

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

shipping ocoosys:

• cost: $13.99
• transit: 2-4 Days
• type: Fixed
• service: Expedited
• class: Expedited

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