Easy Air Ride 165 – 200 PSI Pressure Switch is theoretically the most intricate component of any onboard air system. Think of it simply as the brain of the operation.

The Specs

Our pressure switch features dual five-inch integrated Lead Wires. These wires are non-polar, meaning it doesn’t matter which wire you use for your ground or your trigger—making your installation fast and foolproof. To ensure long-term durability, the lower body of the switch and the wire entry points are encased in a protective rubberized coating. This provides a rugged barrier against road grime and moisture, making it the perfect choice for mounting your air tank under the bed of a truck or anywhere else exposed to the elements.

How it Operates

The switch is designed to mount directly to your air tank, threading into any 1/4 inch NPT orifice. Its job is simple but vital: when your tank pressure drops to 165 PSI, the switch wakes up and triggers your compressors. Once the tank reaches a solid 200 PSI, the pressure switch signals them to shut down.

The 1-2-3 Easy Install 

Step One: Connect to switched key power -take either one of the two lead wires from the pressure switch and connect it to a 12V switched ignition source (such as your accessory circuit, wiper motor, or cigarette lighter). This ensures your entire air ride system automatically shuts off when the vehicle is turned off, preventing your battery from draining overnight.

Step Two: Connect to the relay trigger – take the remaining wire from the pressure switch and run it directly to terminal 86 on your compressor relay. Because our premium pressure switch is non-polar, it does not matter which wire you chose for Step 1 – and which one you use here—the switch simply acts as an intelligent gatekeeper, passing 12V power to the relay only when your tank needs air.

Step Three: To complete the circuit, ensure terminal 85 on your relay is connected to a solid, clean chassis ground with direct metal-to-metal contact. For maximum performance and the fastest recovery times, always have your engine running while the system is pumping. This ensures your compressors receive full alternator amperage, keeping them running cool, fast, and efficient while protecting your battery.

The Vital Role of the Relay

It is imperative to understand that while the pressure switch is the brain of your system, it is not the muscle.

These poor switches get ridden hard and put away wet—literally. Threaded directly into a dark, damp air tank, they are subjected to constant moisture and grueling pressure cycles, yet they are expected to work perfectly every single time. But as vital as this brain is, it is structurally delicate; it is only designed to handle a tiny, low-amperage electronic signal.

Your compressor, on the other hand, is the pure muscle. It is hungry, aggressive, and wants to pull 20+ amps of heavy juice.

You should never wire a compressor directly to a pressure switch without a relay. Doing so forces that massive, hungry amperage straight through the delicate switch and your vehicle’s factory ignition switch. Without the relay acting as a protective barrier, you can create a severe melting hazard within your dash wiring, ultimately frying your components and possibly causing a total system failure.

By using a relay, the switch safely passes a tiny signal to trigger the circuit, allowing the relay to handle the heavy electrical beating and feed the compressor the raw power it needs.

Pro-Tips from the Shop 

Over the years, we’ve learned a few rugged tricks to beat the elements and prolong the life of your pressure switch:

 The Velocity Effect: Think about it—every time you hit a switch, you create a high-speed rush of air inside that tank. If there is any standing water at the bottom, that extreme velocity atomizes the water into a fine, pressurized mist that coats the tank walls and washes right into your pressure switch. Over time, that constant moisture corrodes the internals of the switch, causing mixed signals, a compressor that runs sporadically, or a system that won’t run at all. Keep that tank dry!

The Elite Offset:If you are running one of our popular Elite Kits, you have a massive advantage. Our premium manifolds feature built-in auxiliary ports. By using a simple 1/8″ female NPT by 3/8″ male NPT brass reducer, you can thread your pressure switch directly into the manifold itself. This completely isolates the switch from the tank, keeping it a few inches further away from the walls and entirely out of the splash zone.

 The 90° Street Elbow Hack: If you are mounting your switch directly to an air tank port you can pick up a 90° brass street elbow and point it upward. That simple turn will help block high-pressure moisture from blasting directly into the delicate sensor throat. It acts as a shield, forcing condensation to hit the brass wall and drop back into the tank rather than soaking your switch.

The EZ Tank Drain Advantage

No onboard air system should ever be without our EZ Tank Drain Valve. Ditch that old-school, painful butterfly petcock that forces you to practically lay in your trunk with a wrench in one hand, a rag in the other, and a catch pan underneath just to keep high-pressure water from spraying all over the place. Our valve makes regular draining effortless, which is the ultimate defense against the Velocity Effect.

Lastly – Glove Box Insurance

At the end of the day, these are electronic components operating inside a harsh, dark, damp cave of moisture. Even the best ones can wear out over time. Keeping a spare switch in your glove box is a cheap insurance policy. It’s a 2-minute fix on the side of the road that ensures your compressors keep running happily for a long time to come.

Technical Diagnostics – Symptoms & Solutions 

Note:  Our premium heavy-duty pressure switches utilize a sealed mechanical pressure diaphragm that is factory calibrated and 100% tested. Mechanical failure out of the box is virtually non-existent. If your system is experiencing issues, check the real-world scenarios below before assuming you have a defective component.

Symptom: Compressors run constantly and will not shut off at 200 PSI.

 PLEASE SELECT YOUR EXACT SCENARIO BELOW:

SCENARIO A: THIS IS A BRAND-NEW INSTALLATION (INITIAL FILL)

 Solution 1: The Initial Fill Illusion (Understanding System Volume). If this is the very first time you are turning the key to fill your brand-new system, your compressors are working exactly like they are supposed to. You aren’t just filling a 6 Plus-gallon chamber; you are filling 50 to 60 feet of plumbing lines, internal manifold blocks, gauge lines, and four massive, empty rubber airbags that swallow volume for breakfast. If your 12V pump has only been running for 10 or 15 minutes, it isn’t broken—it just isn’t finished priming the maze yet.

 Solution 2: Skip the Staged Fill (Use the Quick Connect). Our Air Suspension Kits provide a custom premium air quick-connect assembly with a Schrader valve explicitly so you don’t punish your 12V pump on the initial fill. You must pre-charge the system using an external shop compressor first. Keep in mind: standard single-stage garage compressors are physically limited and will only pre-charge your system to about 80 or 90 PSI. Once your shop compressor stalls out, disconnect it, turn your vehicle’s engine on, and let our heavy-duty 12V workhorse finish the heavy lifting from 90 to the full 200 PSI shut-off mark.

All initial fills vary depending on the length of the vehicle, how much airline was used, and how it was routed—a long-wheelbase Cadillac or a Parkwood Wagon takes more volume than a standard coupe. A complete initial fill can very well take upwards of 30 minutes plus total. Even though our compressors are 100% duty cycle workhorses, it is best practice to break in any brand-new compressor on its initial run. We highly recommend cycling the system for 10 minutes, giving it a quick breather to cool down, and then running it for another 10 minutes. This may take you several cycles to completely reach 200 PSI, but it ensures your equipment breaks in perfectly for the long haul.

 Solution 3: Bypassed Relay Gate (Wiring Error). If the system has been pre-charged completely, has cycled for over 30 minutes, and still won’t cut power, the mechanical switch isn’t the problem—your wiring is bypassing the relay gate. Check Terminal 87 and Terminal 30 on your compressor relay. If your main 12V key-power or the compressor trigger wire is hooked up directly to a constant battery source without passing through the relay’s internal interrupt switch, the pumps will run continuously until the battery dies, completely ignoring the pressure switch signal.

SCENARIO B: THIS IS AN EXISTING SYSTEM (RUNNING FOR MONTHS OR YEARS):

Solution 1: Moisture Corrosion (The Reality of the Damp Tank). If your system has worked flawlessly for years and suddenly refuses to shut off or starts cycling erratically, 9 times out of 10, the pressure switch has finally seen better days. Most people new to air ride don’t realize you have to drain your tank periodically to keep the system dry. Over the years, that constant atmospheric moisture and velocity mist inside the tank floods the delicate internals of the switch, eventually causing the electrical points to stick.

The Fix: It’s time to replace the pressure switch. And since your relay is just as old and has been working just as hard right alongside it, best shop practice is to change the relay at the exact same time. Treat them as a team, put fresh terminals on, and you’re good to go.

SYMPTOM: Compressors will not turn on at all, even when the air tank is completely empty.

PLEASE SELECT YOUR EXACT SCENARIO BELOW:

SCENARIO A: THIS IS A BRAND-NEW INSTALLATION

 Solution 1: The Paint and Rust Trap (Bad Chassis Ground). This is the single most common installation error in the book. A relay requires a flawless, 100% bare metal-to-metal connection to ground the circuit and trigger the pumps. Do not just loop your wire around a factory bolt on the trunk floor or on the underside of the frame and assume it’s grounded just because it’s metal. Paint, powder-coating, rust, and road grime are heavy insulators that completely block electrical current.

The Fix: Take a piece of sandpaper or a wire wheel and grind that mounting location down to shiny, raw steel before securing your ground wire.

 Solution 2: Phantom Ignition Sources & Half-Crimp Leads. Just because your vehicle starts up doesn’t mean your 12V ignition trigger wire is actually getting power. If you used a bad crimping tool or didn’t strip the wire cleanly, the copper core inside your lead wire might not even be touching the terminal.

The Fix: Verify that one leg of your pressure switch is spliced into a true 12V key-switched accessory circuit that stays hot when the vehicle is running. Ensure your crimp connections are tight and solid—give them a firm tug. The second leg of your pressure switch must run directly to Terminal 86 on your relay, while Terminal 85 handles that clean ground you just sanded.

 Solution 3: Trust the Tech (Check the Green LED). We engineered our advanced systems to take the guessing out of garage diagnostics. Check the indicator on your unit: Is our signature green LED diagnostic light lit up? If that green LED is glowing, it mathematically proves that your ignition source, your pressure switch, and your wiring are completely healthy and sending the proper signal. If the light is on but the pump is dead, stop looking at the switch and go check your heavy-duty main battery fuse or the pump’s direct ground lead.

SCENARIO B: THIS IS AN EXISTING SYSTEM (RUNNING FOR MONTHS OR YEARS)

 Solution 1: Corroded Ground or Blown Inline Fuse. If your older system suddenly goes completely silent, the environment has likely caught up to your wiring. Salt, moisture, and road vibration underneath a classic truck will corrode an exposed chassis ground over time, breaking the electrical connection.

The Fix: Inspect the main heavy-gauge power wire running from your battery to Terminal 30 on the relay and check the inline fuse holder—if the fuse is blown, replace it. If the fuse is good, take apart your relay and compressor ground locations, clean away the fresh rust or corrosion down to bare metal, and re-secure them.

Note from EZ AIRRIDE: Our mission is to provide the classic vehicle community with the ultimate blueprint for reliable, hard-hitting air suspension. We are constantly expanding this master tech database to keep our fellow builders on the road.

If you encountered a unique wiring symptom or discovered a unique garage hack that we didn’t cover here, we want to hear about it. Help us help the rest of the air ride world by sending your verified symptom and solution directly to our team.

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