Viair 90113 Pressure Switch with Relay 1/8 in. NPT - Reliable 12V

In this review the Viair 90113 Pressure Switch with Relay is evaluated as a compact, utilitarian solution for automotive and mobile air systems that need an automatic on/off control at specific pressures. The single biggest reason to buy is its dependable switching behavior: it turns on at 90 PSI and off at 120 PSI, which makes it well suited for users who need a simple, rugged control device for 12-volt compressors. The unit is clearly aimed at installers who value a sealed, long-life component with pre-fitted terminals for fast hookup.

Key Features

• Operating pressures: The 90 PSI on / 120 PSI off set points provide a clear pressure window for automatic compressor control without constant monitoring.
• 12-volt compatibility: Rated for 40 amps on 12-volt systems so it can handle typical automotive air compressors when wired correctly.
• Durable cycle life: Tested to last over 10,000 cycles which gives confidence for repeated use in mobile setups and frequent-duty applications.
• Pre-fitted terminals: Leads come with insulated male push-to-connect terminals that are clearly marked, speeding up installation and reducing wiring mistakes.
• Moisture resistance: The sealed construction helps protect the switch and relay from moisture for reliable field use.
• Compact footprint: At roughly 4.25 in long and 2.25 in wide and high, the unit packs the relay and switch into a small housing for tight mounting locations.

Who It's For

This pressure switch is best for DIYers, off-road enthusiasts, and tradespeople who run small to medium 12-volt air compressors in trucks, trailers, or mobile rigs and need an automatic cutoff at a specific pressure range. Its pre-fitted terminals and simple pressure set points appeal to anyone wanting a quick, reliable replacement or upgrade for an existing system.

Those who need variable or custom pressure ranges, multi-voltage compatibility, or continuous higher-amp switching should look elsewhere, as this model is fixed to a 90/120 PSI trip and is intended for 12-volt circuits up to 40 amps.

Pros & Cons

Pros

• Clear and useful pressure set points that suit many automotive air setups.
• Robust construction and sealed body improve longevity in damp or dirty environments.
• Pre-marked, insulated push-to-connect leads make installation fast and less error-prone.
• Compact size fits in tight mounting spaces common on vehicles and trailers.

Cons

• Some users report seasonal lifespan concerns, so long-term durability can vary by application intensity.
• Fixed pressure tolerance of 5% means it is not adjustable for precise calibration needs.

Specifications

Operating pressure	90 PSI on / 120 PSI off
Thread size	1/8 in. Male NPT
Amp rating	40 amps (12-volt systems)
Cycle life	Tested over 10,000 cycles
Sealing	Sealed for moisture resistance
Dimensions	4.25 in L x 2.25 in W x 2.25 in H
Tolerance	5%

Our Verdict

The Viair 90113 Pressure Switch with Relay is a practical, cost-effective choice for anyone needing a straightforward automatic control for 12-volt air compressors. It offers durable construction, easy installation, and clearly defined pressure switching that make it a good value for replacement parts and mobile setups, provided the 90/120 PSI range and 40 amp limit match the intended application.

Frequently Asked Questions

Can this be used on 24-volt systems?
No. This unit is specified for 12-volt systems only and is rated for 40 amps at that voltage.

How are the wires connected?
The leads are pre-fitted with insulated male push-to-connect terminals that are clearly marked to simplify correct wiring.

Is the switch weather resistant?
Yes. The housing is sealed for moisture resistance, which helps in damp or outdoor installations.