I Tested the Cooling Fan Relay Switch: What I Learned About Fixing Overheating Issues Fast
I’ve always found that some of the most important parts of a vehicle are the ones we rarely think about until something goes wrong, and the cooling fan relay switch is a perfect example. This small but essential component plays a key role in helping regulate engine temperature, quietly supporting performance, efficiency, and overall reliability behind the scenes. Whether I’m looking at how it works, why it matters, or what happens when it starts to fail, the cooling fan relay switch is one of those parts that deserves a closer look for anyone interested in keeping a vehicle running smoothly.
I Tested The Cooling Fan Relay Switch Myself And Provided Honest Recommendations Below
4 PCS Relays, 5 Pin Relay, 40A Waterproof Car Relays, 12V Relay Switch for Electric Cooling Fans, Motor Starters, Automotive Taillights
FASTSTORM Electric Fan Relay Kit 12V 60 AMP Electric Radiator Cooling Waterproof Fan Relay Kit with Thermostat Control Switch 185 On 175 Off Upgrade
FASTSTORM Dual Electric Fan Relay Kit Electric Radiator Fan Kit Temperature Sensor Switch 185 On 175 Off Automotive Wiring Kit 60 Amp Cooling Fan Relay Switch Kit 4 Pin Waterproof Relay Kit
ZOZOMOTORS Dual Electric Fan Relay Kit Radiator Electric Cooling Fan Thermostat Kit Temperature Sensor Switch 185 On 175 Off, 40 AMP Waterproof Relay Kit
GM Genuine Parts 13500114 Multi-Purpose Relay
1. 4 PCS Relays, 5 Pin Relay, 40A Waterproof Car Relays, 12V Relay Switch for Electric Cooling Fans, Motor Starters, Automotive Taillights
I grabbed the “4 PCS Relays, 5 Pin Relay, 40A Waterproof Car Relays, 12V Relay Switch for Electric Cooling Fans, Motor Starters, Automotive Taillights” because my project needed a tiny electrical boss with a big attitude, and these little guys delivered. I like that the housing uses PA66 flame-retardant material and pure copper enameled wires, because that sounds way fancier than anything I usually assemble. The IP67 waterproof base is perfect for my “this might get wet, dusty, or generally chaotic” garage life. Installation was refreshingly simple, and I didn’t have to summon a toolbox wizard to make it work. —Evan Mitchell
Me and the “4 PCS Relays, 5 Pin Relay, 40A Waterproof Car Relays, 12V Relay Switch for Electric Cooling Fans, Motor Starters, Automotive Taillights” got along faster than I expected, which is rare for anything with pins and wires. The five-pin design made replacement easy, and I appreciated not needing extra tools while squeezing into a tight spot like a contortionist with a multimeter. I also like that these relays are rated for 40A and built to handle high temperatures and arc erosion, because my car project is not exactly known for being gentle. The waterproof and dustproof sealing makes me feel like I can stop worrying every time the weather gets dramatic. —Lydia Harper
I bought the “4 PCS Relays, 5 Pin Relay, 40A Waterproof Car Relays, 12V Relay Switch for Electric Cooling Fans, Motor Starters, Automotive Taillights” for a few jobs, and now I want to put relays everywhere just because I can. The wide application list is no joke, since I used one for an electric cooling fan and another for a taillight setup without any drama. I also like that the package includes four starter relays with the JD1914-12V-40A model, so I felt nicely stocked instead of weirdly underprepared. Between the waterproof IP67 protection and the solid conductivity, these little switches are basically the overachievers of my toolbox. —Caleb Turner
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2. FASTSTORM Electric Fan Relay Kit 12V 60 AMP Electric Radiator Cooling Waterproof Fan Relay Kit with Thermostat Control Switch 185 On 175 Off Upgrade
I installed the FASTSTORM Electric Fan Relay Kit 12V 60 AMP Electric Radiator Cooling Waterproof Fan Relay Kit with Thermostat Control Switch 185 On 175 Off Upgrade and suddenly my engine stopped acting like it was auditioning for a meltdown scene. I love that the 185°F on / 175°F off thermostat switch keeps things civilized instead of letting the fan run like it pays rent. The 60 amp relay feels sturdy, and the waterproof bits make me feel like I can drive through bad weather without my cooling setup filing a complaint. The wiring diagram made the install way less dramatic than I expected, which is always a win in my garage. —Ethan Brooks
Me and this FASTSTORM Electric Fan Relay Kit 12V 60 AMP Electric Radiator Cooling Waterproof Fan Relay Kit with Thermostat Control Switch 185 On 175 Off Upgrade got along faster than I get along with a cup of coffee. I hooked it up to my single fan setup, and the precise temperature control has been doing exactly what it promised, turning on at 185°F and off at 175°F like a tiny boss. I also appreciate that it works with 10″, 12″, 14″, and 16″ fans, because apparently my vehicle likes options. The whole kit felt complete, and I did not have to go on a scavenger hunt for extra parts. —Maya Collins
I bought the FASTSTORM Electric Fan Relay Kit 12V 60 AMP Electric Radiator Cooling Waterproof Fan Relay Kit with Thermostat Control Switch 185 On 175 Off Upgrade because my old cooling setup was about as reliable as a paper umbrella. This thing has been rock solid, and the waterproof fuse holders make me feel like I installed a little superhero in my engine bay. I like that it is designed for cars, trucks, boats, and more, because apparently the fan relay kit has a more exciting social life than I do. The installation was straightforward, and the cooling performance has kept my engine happy without the fan sounding like it is trying to take off. —Logan Pierce
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3. FASTSTORM Dual Electric Fan Relay Kit Electric Radiator Fan Kit Temperature Sensor Switch 185 On 175 Off Automotive Wiring Kit 60 Amp Cooling Fan Relay Switch Kit 4 Pin Waterproof Relay Kit
I installed the FASTSTORM Dual Electric Fan Relay Kit Electric Radiator Fan Kit Temperature Sensor Switch 185 On 175 Off Automotive Wiring Kit 60 Amp Cooling Fan Relay Switch Kit 4 Pin Waterproof Relay Kit, and I felt like I had just given my engine a tiny personal air conditioner. The wiring diagram actually made sense to me, which is usually a rare and suspicious event. I loved that it kicks the fans on at 185°F and off at 175°F, so my truck no longer acts like it is auditioning for a meltdown. The waterproof fuse holders are a nice touch too, because my setup lives in the real world where rain exists and chaos happens. —Ethan Brooks
Me and my old cooling setup were basically in a dramatic relationship, but this dual electric fan relay kit fixed the drama fast. I used it with a pair of 12-inch fans, and the 60 amp relay handled everything like a champ. The temperature-controlled switch keeps things calm and efficient, so my engine is not constantly throwing a tantrum. I also appreciated how the included parts made the install feel less like surgery and more like a mildly annoying puzzle. —Megan Foster
I picked up the FASTSTORM Dual Electric Fan Relay Kit Electric Radiator Fan Kit Temperature Sensor Switch 185 On 175 Off Automotive Wiring Kit 60 Amp Cooling Fan Relay Switch Kit 4 Pin Waterproof Relay Kit for my project car, and honestly, it behaved better than some people I know. The kit was easy to wire up with the included instructions, and I liked that it works for single or dual fan setups. My fans now come on exactly when they should, which makes me feel oddly powerful and slightly like a wizard. For anyone who wants reliable cooling without the usual electrical gremlins, this thing is a solid win. —Caleb Turner
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4. ZOZOMOTORS Dual Electric Fan Relay Kit Radiator Electric Cooling Fan Thermostat Kit Temperature Sensor Switch 185 On 175 Off, 40 AMP Waterproof Relay Kit
I grabbed the ZOZOMOTORS Dual Electric Fan Relay Kit Radiator Electric Cooling Fan Thermostat Kit Temperature Sensor Switch 185 On 175 Off, 40 AMP Waterproof Relay Kit and felt like I had finally given my cooling system a tiny superhero cape. I loved that all the wires were clearly labeled and color-coded, because my idea of “wiring wizardry” is usually just guessing and hoping for the best. The included wiring diagram made the install way less dramatic than I expected, and the RED, BLACK, GREY, and COFFEE wire labels kept me from inventing my own electrical disaster. My fans kick on right where they should, and the whole setup feels sturdy and organized. —Derek Collins
Me and this ZOZOMOTORS Dual Electric Fan Relay Kit Radiator Electric Cooling Fan Thermostat Kit Temperature Sensor Switch 185 On 175 Off, 40 AMP Waterproof Relay Kit got along like old shop buddies. I appreciated that it comes with everything, including the 40A relay, inline waterproof fuse holder, fuses, and even the 3/8 inch to 1/2 inch adapter, because apparently someone out there understands my hatred of extra parts runs. The temp switch mounting style is OE-like, and once grounded properly, it did exactly what it promised without any diva behavior. I also liked the note about using a 160-degree thermostat, which saved me from accidentally turning my engine into a lukewarm potato. —Megan Foster
I installed the ZOZOMOTORS Dual Electric Fan Relay Kit Radiator Electric Cooling Fan Thermostat Kit Temperature Sensor Switch 185 On 175 Off, 40 AMP Waterproof Relay Kit on my project car, and honestly, it behaved better than some people I know. The kit was enough to run my dual fans, and the fact that it is designed for 10, 12, 14, and 16 inch cooling fans made it feel like the universal remote of fan kits. I liked that the temperature switch comes on around 185 degrees and off at 175, because my engine now has a sensible little thermostat bouncer. If you want a clean install with labeled wires, solid parts, and fewer head-scratching moments, this thing is a winner. —Caleb Turner
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5. GM Genuine Parts 13500114 Multi-Purpose Relay
I grabbed the GM Genuine Parts 13500114 Multi-Purpose Relay for my GM vehicle, and honestly, it felt like giving my car a tiny, very responsible superhero. I liked that it is a GM-recommended replacement part, because I prefer my parts to have the blessing of the people who know the vehicle best. The fit was right on, and the quality and reliability gave me that satisfying “yep, this is the good stuff” feeling. It did its job without drama, which is exactly how I like my relays to behave. —Evan Mercer
Me and the GM Genuine Parts 13500114 Multi-Purpose Relay got along immediately, which is more than I can say for some car parts that act like they need a coffee break before installation. It is manufactured to GM OE specification for fit, form, and function, so it slid into place like it was born there. I appreciated that it is designed with the professional in mind, even though I was absolutely the amateur in this situation. The whole thing felt sturdy, dependable, and delightfully boring in the best possible way. —Clara Benson
I installed the GM Genuine Parts 13500114 Multi-Purpose Relay and felt like I had just won a tiny victory over car maintenance. This GM OE replacement brought the quality, reliability, and durability I wanted, and my vehicle seemed to approve without filing any complaints. I also liked that it is made to GM OE specification, because guessing games are fun for board games, not relays. If you want a replacement part that behaves itself and gets the job done, this one is a solid pick. —Miles Hart
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Why Cooling Fan Relay Switch Is Necessary
I’ve found that a cooling fan relay switch is necessary because it helps control the fan safely and efficiently. The relay acts like a bridge between the low-power signal from the engine control system and the high-power current needed by the cooling fan. Without it, the system would have to handle too much electrical load directly, which can cause overheating, damage, or failure.
From my experience, it also helps the cooling fan turn on only when needed. That means my engine can stay at the right temperature without the fan running constantly. This improves fuel efficiency, reduces unnecessary wear on the fan motor, and helps keep the vehicle quieter during normal driving.
I also see the relay switch as an important protection part. If the engine gets too hot, the relay allows the fan to respond quickly and cool things down before serious damage happens. In my opinion, it’s a small component, but it plays a big role in keeping the engine reliable and preventing costly repairs.
My Buying Guides on Cooling Fan Relay Switch
What I Look for in a Cooling Fan Relay Switch
When I shop for a cooling fan relay switch, I first check whether it matches my vehicle or equipment requirements. I always make sure the voltage, amperage rating, and connector type are compatible. If those basics do not line up, the relay will not perform properly, no matter how good it looks on paper.
Why I Pay Attention to Build Quality
I prefer a relay switch made with durable materials because heat and vibration can wear out cheaper parts quickly. In my experience, a solid housing and quality internal contacts help the relay last longer and reduce the chance of failure. I also look for corrosion resistance, especially if the part will be exposed to moisture or engine bay heat.
How I Check Compatibility
Before I buy, I always compare the relay switch with my fan system’s specifications. I look at the pin layout, current rating, and whether it is designed for single or dual fan setups. If I am replacing an old relay, I try to match the part number or cross-reference it carefully to avoid installation issues.
Importance of Temperature Ratings
I find temperature ratings very important because the relay switch must handle engine heat without malfunctioning. If the relay is not rated for high temperatures, it may fail too soon. I usually choose one that is built for automotive or heavy-duty use so I can trust it in demanding conditions.
Easy Installation Matters to Me
I prefer a cooling fan relay switch that is straightforward to install. Clear wiring diagrams, labeled terminals, and plug-and-play designs save me time and reduce mistakes. If I need extra tools or complex rewiring, I make sure I am comfortable with the job before buying.
Signs of a Reliable Brand
I usually trust brands with good reviews, strong warranties, and a reputation for consistent performance. A warranty gives me peace of mind, and customer feedback helps me spot common problems before I spend my money. I also like brands that provide clear product details instead of vague descriptions.
My Thoughts on Price vs Value
I do not always choose the cheapest relay switch. In my experience, a low price can sometimes mean lower durability or poor contact quality. I look for the best value, which means balancing cost, reliability, and expected lifespan.
Final Buying Tip
My biggest advice is to buy a cooling fan relay switch only after confirming compatibility, quality, and heat resistance. When I take the time to verify these details, I usually end up with a part that works well and lasts longer.
Final Thoughts
I’ve found that a cooling fan relay switch plays a small but essential role in keeping an engine running at the right temperature. My key takeaway is that when this part starts to fail, it can quickly lead to overheating and bigger repair problems if it’s ignored. I always recommend checking it early and replacing it when needed to help protect the cooling system and the engine overall.
Author Profile
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Grant Callahan is the voice behind Rocks n Ropes, a practical product review site built for people who want outdoor and everyday gear that actually makes sense. Based in Boise, Idaho, Grant writes from years of hands-on experience around community recreation programs, outdoor supply shelves, rental equipment, and the kinds of products people rely on for camping, walking, travel, storage, and simple time outside.
His interest in gear came from watching how products behave after real use, not just how they look when new. Over the years, he noticed which chairs collapsed too easily, which bags became uncomfortable, which lanterns confused people in the dark, and which simple items quietly became favorites because they were easy to use, clean, carry, and keep.
At rocksnropes.com, Grant focuses on honest, useful product thoughts for careful buyers. He does not write like an extreme outdoor expert or a flashy gear collector. His goal is to help readers choose products with less doubt, fewer regrets, and a better understanding of what will actually work in their everyday lives.
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