How is a pressure switch different from a pressure sensor?

A switch changes state at a single setpoint; a sensor reports the exact pressure continuously. Switches are cheaper and need no signal conditioning, ideal for alarms and cut-offs; sensors suit measurement and control. Many vehicles use both.

What is the difference between SPST and SPDT?

SPST has one contact that opens or closes at the setpoint. SPDT has a common terminal plus normally-open and normally-closed contacts, switching one circuit off while switching another on.

What does isolated vs non-isolated mean?

Non-isolated switches reference the contacts to the body/ground; isolated switches separate the contacts electrically from the port and housing to avoid ground loops and control a floating circuit.

What is setpoint and deadband (hysteresis)?

The setpoint is the pressure at which the switch changes state; the deadband is the gap between trip and reset points that prevents chatter. Both are set to requirement, with tolerances as low as ±3 psi.

Can a pressure switch drive a lamp or relay directly?

Yes, within its rated contact load a switch can energise a warning lamp, buzzer or relay coil directly. For higher loads it drives a relay or solid-state module.

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Automotive Pressure Switches

Rugged on/off pressure switches that trip a contact at a precise setpoint — for warning lamps, compressor cut-out and system protection. SPST / SPDT, isolated or non-isolated, ±3 psi setpoint tolerance, -40°C to +150°C, IP67. No ECU required.

Common Uses:

Low Oil Pressure Warning
HVAC Compressor Cut-Out
Hydraulic System Protection

Automotive SPST and SPDT pressure switches with brass, aluminium and stainless steel housings, IP67, -40°C to +150°C

PSW

Switch Specs:

Operating Range

-40°C to +150°C

Contacts

SPST / SPDT · Isolated

Protection

IP67 · ±3 psi setpoint

Configure a switch Request OEM Quote

Need a continuous pressure reading instead? See pressure sensors →

-40°C to +150°C±3 psi setpointIP67SPST / SPDTIsolated / Non-isolatedAir / Oil / Coolant / Water

How a pressure switch works

A diaphragm or piston acts against a calibrated spring. When pressure crosses the setpoint the mechanism snaps an electrical contact open or closed — driving a lamp, relay or protection circuit directly.

Setpoint

The pressure at which the contact changes state, calibrated to ±3 psi.

Deadband / hysteresis

The gap between trip and reset points that prevents contact chatter.

SPST vs SPDT

Single make/break, or common + NO + NC for dual-circuit switching.

Isolated / non-isolated

Contacts floating from the body, or body-referenced to ground.

Where threshold switching matters

Switches are specified when the system only needs to know it has crossed a limit — for alarms, cut-offs and protection.

Low Oil Pressure Warning

Trips the dashboard warning lamp the instant oil pressure drops below the safe setpoint — the classic engine-protection switch, no ECU required.

HVAC Compressor Cut-Out

High- and low-pressure switches protect the A/C compressor by cutting the clutch circuit outside the safe refrigerant pressure window.

Hydraulic System Protection

Setpoint switches signal over- or under-pressure in steering, brake and auxiliary hydraulic circuits to trigger relief or shutdown.

Pump & Fan Control

Pressure-actuated switching to cut in/out pumps and cooling fans, holding system pressure between two thresholds via deadband.

Brake Pressure Warning

Detects loss of brake-line pressure and energises a warning circuit in safety-critical braking systems.

Air System Limit Switching

Pneumatic and air-brake reservoirs use threshold switches to signal compressor cut-in and low-pressure alarms.

Switch specification selector

Pick the switch type, setpoint and mechanical options. The specification summary assembles below — submit it as an RFQ and our engineering team will quote against your circuit.

Switch type

Contact configuration

Setpoint5.0 bar

0.2 bar±3 psi tolerance · deadband specified separately32 bar

Connection port

Housing material

Mating connector

Specification summary

Switch type: SPST
Contact configuration: Non-isolated
Setpoint: 5.0 bar
Pressure port: M10 × 1 Straight
Housing material: Brass
Mating connector: Terminal Technologies · TTP-SS3FN (IP67)

Technical Specifications

Setpoint and deadband calibrated per customer drawing. Contact us for an OEM quotation.

Pressure Switch Series

Temperature Range

-40°C to +150°C

Switch Types

SPST / SPDT

Configuration

Isolated / Non-isolated

Setpoint Tolerance

As low as ±3 psi

Protection Rating

IP67

Housing Materials

Brass / Aluminium / Stainless Steel

Sensing Media

Air / Coolant / Water / Oil

Customisation

Setpoint and deadband per customer request

Pressure Switch FAQ

Knowledge Base

Frequently Asked Questions

Engineering answers to the questions our customers ask most often.

A pressure switch opens or closes an electrical contact when pressure crosses a preset setpoint. Unlike a sensor it gives no continuous reading — it is a rugged on/off output used to trigger a warning lamp, relay or protection circuit, often without any ECU.