FOUR SEASONS 21787DHYR Control Relay A/c

( Brand: Four Seasons ), ( Manufacturer Part Number: 21787DHYR ), ( Part Type: Control ), ( Manufacturer Warranty: 12 Month Warranty ), ( Notes: A/c Compressor Control Relay 6 Term. ), ( Years: 1989 1995 1996 1997 1998 ), ( Application: Nissan Sentra A/c Control Relay ), ( Product Name 2: A/c Compressor Control Relay ), ( Cs-sku: 400 )

Review FOUR SEASONS Nissan A/c Control Relay fits SENTRA 1989–1998

The **Seasons 21787DHYR A/C Control Relay** is a high-quality, direct-fit replacement designed to restore optimal climate control functionality to **1995-1998 Nissan Sentra** models, as well as compatible with **1989-1996 Nissan Sentra** and **1997** variants. Engineered to meet or exceed OEM specifications, this relay ensures seamless operation of the air conditioning system by regulating electrical flow to the compressor clutch, preventing overheating, and maintaining consistent cooling performance. Crafted from durable, corrosion-resistant materials, it is built to withstand the demands of daily use while providing reliable, long-lasting operation. The relay features a robust spring-loaded mechanism for precise engagement and disengagement, reducing wear on the A/C system components and minimizing the risk of electrical shorts or intermittent failures. Its compact yet sturdy design ensures a perfect fit within the vehicle s wiring harness, eliminating the need for modifications or additional adapters. Whether addressing a faulty relay causing erratic cooling, a non-responsive A/C compressor, or persistent electrical issues, this replacement part delivers the performance and reliability expected from an original equipment component. Ideal for both professional mechanics and DIY enthusiasts, the Seasons relay offers a cost-effective solution to restore your Nissan Sentra s climate control system to peak efficiency, ensuring comfort and reliability in every driving condition.

### Pros and Cons of buying a A/C Control Relay (Seasons 21787DHYR) for a 1995-1998 Nissan Sentra (and 1989-1997 models)

1. **Compatibility** The relay is designed to fit multiple Nissan Sentra models (1989 1997, with some overlap into 1998), ensuring broad use without needing a model-specific part. This reduces the risk of purchasing a wrong component if you re unsure of your exact year or trim.

2. **Reliability** A genuine or high-quality aftermarket relay from a reputable brand (like Seasons) is built to handle the electrical load of the A/C system, reducing the risk of failure or damage to other components. Poor-quality relays can cause intermittent issues or even short circuits.

3. **Ease of Installation** Relays are simple to replace, typically requiring only basic tools (screwdriver, wire cutters/strippers if needed) and minimal wiring knowledge. Most Sentras have accessible relay blocks under the dashboard or in the engine bay, making the job straightforward for a DIYer.

4. **Cost-Effective Fix** A faulty A/C control relay is a common cause of A/C system malfunctions (e.g., compressor not engaging, blower motor issues, or erratic fan speeds). Replacing it is far cheaper than diagnosing other potential problems (like a faulty compressor clutch, pressure switch, or control module).

5. **Prevents Further Damage** A bad relay can cause electrical surges that may damage the A/C compressor, blower motor, or control board. Replacing it early can save money on more extensive repairs down the line.

6. **Warranty or Return Options** Purchasing from a trusted seller (online retailer, auto parts store, or dealer) often includes warranties or return policies, giving you peace of mind if the relay fails prematurely.

7. **Universal Fit** Since it covers multiple years, it s a convenient "one-size-fits-most" solution, especially if you re unsure about your exact model or if you plan to use it in a different Nissan vehicle later.

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1. **Potential Counterfeit or Low-Quality Parts** Some aftermarket relays, especially those from unbranded or third-party sellers, may be counterfeit or poorly manufactured. This can lead to early failure, poor electrical contacts, or even fires in extreme cases. Always buy from reputable sources (e.g., OEM suppliers, Amazon with verified sellers, or auto parts stores like AutoZone, RockAuto, or local dealers).

2. **Incorrect Part Number or Fit** While the relay is listed as compatible with multiple years, there may be slight variations in wiring or mounting between models. Double-check that your Sentra s relay block layout matches the relay s pin configuration (some relays have color-coded or numbered terminals). A miswired relay can cause electrical issues or damage.

3. **Symptoms May Indicate Other Problems** If the A/C relay is replaced but the issue persists (e.g., compressor still doesn t engage, fan speeds are erratic), the problem might be elsewhere (e.g., faulty compressor clutch, low refrigerant, blown fuse, or a bad control module). This could lead to unnecessary replacements if the root cause isn t diagnosed properly.

4. **Limited Lifespan** Relays are durable but not indestructible. If your Sentra s A/C system is frequently used in extreme conditions (e.g., high heat, frequent on/off cycling), the relay may wear out faster than average. In such cases, a higher-quality relay or a fuse/relay block upgrade might be worth considering.

5. **DIY Risk for Inexperienced Users** While simple, wiring mistakes can occur if you re unfamiliar with electrical systems. Incorrectly connecting the relay could short-circuit components or render the A/C system inoperable. If unsure, consulting a mechanic or watching a detailed installation video is advisable.

6. **Price Variability** Prices for aftermarket relays can vary widely depending on the seller. Some "deals" may be too good to be true, indicating counterfeit or low-quality parts. Researching average prices (e.g., $10 $30 for a reputable brand) can help avoid overpaying or getting a dud.

7. **Environmental Factors** If your Sentra is exposed to moisture, dust, or extreme temperatures (e.g., parked in a garage with poor ventilation), the relay s contacts may corrode or degrade faster. Regular maintenance (e.g., cleaning the relay block) can mitigate this.

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The **Seasons 21787DHYR A/C control relay** is a practical and cost-effective solution for diagnosing and fixing A/C-related issues in a 1995 1998 (or 1989 1997) Nissan Sentra, provided it is purchased from a trusted source. Its broad compatibility and ease of installation make it a go-to part for common electrical gremlins in the A/C system. However, the risk of counterfeit parts, potential misdiagnosis of symptoms, and the need for careful installation cannot be overlooked.

If you re confident in your ability to diagnose the issue (e.g., testing the relay with a multimeter or replacing it as a last resort), this relay is a solid choice. For those less experienced, verifying the symptoms (e.g., checking for power at the relay terminals, testing fuses, and inspecting the compressor clutch) is crucial before purchasing.

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- The A/C compressor clutch doesn t engage when the A/C is turned on.

- The blower motor runs erratically (e.g., fan speeds don t respond to the control knob).

- The A/C system turns on and off intermittently.

- A clicking noise (but no engagement) when the A/C is activated.

If other components (e.g., fuses, compressor clutch, control module) are suspected, prioritize testing those first.

2. **Buy from a Reputable Source** Purchase the relay from a well-known auto parts retailer (e.g., AutoZone, RockAuto, Amazon with verified sellers, or a local Nissan dealer). Avoid extremely cheap options from unknown sellers, as they may be counterfeit.

3. **Check Compatibility** Ensure the relay s pin configuration matches your Sentra s relay block. Some models may require a relay with specific terminal labels (e.g., 86, 85, 30, etc.). Refer to your Sentra s wiring diagram or a repair manual for confirmation.

4. **Install Carefully** Follow the relay s installation instructions and your vehicle s wiring diagram. If unsure, consult a professional or a detailed video guide. Double-check connections to avoid short circuits.

5. **Test the Fix** After installation, test the A/C system thoroughly. If the issue persists, revisit the diagnosis (e.g., check for low refrigerant, test the compressor clutch, or inspect the control module).

6. **Consider a Relay Block Upgrade (Optional)** If your Sentra experiences frequent relay failures, upgrading to a high-quality relay block (e.g., from a brand like Denso or Bosch) can improve reliability and reduce future issues.

**Final Verdict:** The Seasons 21787DHYR relay is a **worthwhile purchase for a targeted fix** if you ve confirmed the relay is faulty. However, approach the purchase with caution to avoid counterfeit parts or misdiagnosis. For long-term reliability, prioritize quality components and proper installation. If in doubt, consult a mechanic to diagnose the issue before replacing the relay.

Details:

12 Month Warranty Fitment Notes: Vehicle: 1995 - 1998 Nissan Sentra. Parts Geek - For 1995 - 1998 Nissan Sentra A/C Control Relay 21787DHYR 1989 1996 1997: Review Fitment Notes to Ensure Proper Fit condition: New Brand: Four Seasons Notes: Compressor 6 Term. Quality contacts ensure proper conductivity. Vehicle specific applications.

Amperage Rating: 20 Features: OE molded connectors. Precision engineered.

part #: 21787dhyr price

• $28.05

specifications nssnheatcontrol:

• for models: Sentra
• for makes: Nissan
• for years: 1989-1998
• brand: Four Seasons
• mpn: 21787dhyr
• part type: Control
• manufacturer warranty: 12 Month Warranty
• notes: A/c Compressor Control Relay 6 Term.
• years: 1989 1995 1996 1997 1998
• application: Nissan Sentra A/c Control Relay
• product name 2: A/c Compressor Control Relay
• cs-sku: 400

seller nssnheatcontrol:

• city: Rockville Centre, New York
• rating: 98.7%
• # reviews: 327415

payments nssnheatcontrol:

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

general nssnheatcontrol:

• condition: New
• Car Truck Parts Accessories > Air Conditioning Heating > HVAC Controls Control Units

shipping nssnheatcontrol:

• carrier: FedEx
• service: FedEx Ground / FedEx Home Delivery
• transit: 4-7 Days
• type: Fixed
• class: Standard
• cost: $0.00

offer nssnheatcontrol:

• quantity: 1
• sold: 0
• started: April 10, 2026
• options: Ship-to-home
• availability: In Stock

returns nssnheatcontrol:

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

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