Viair Pressure Switch with Built-In 40A Relay

Max Load of 40 Amps & 1/8" NPT


29 reviews


The Viair 40 amp air compressor pressure switch with 40A relay is a rugged and easy to install pressure switch that has a 40 amp relay built-in to increase longevity and decrease install time. This pressure switch will automatically turn your compressor on when the pressure in your air tank falls below a certain pressure and will automatically turn your compressor off when the pressure reaches max pressure, delivering a switch-free and worry-free onboard air experience.

The Viair pressure switch with 40A relay has been tested to last 10,000 cycles with proper maintenance and features clearly labeled lead wires with insulated 1⁄4” male push-to-connect terminals.

    • Moisture resistant
    • Built-in 40 amp relay
    • Viair Pressure Switch w/ Built-in 40 Amp Relay
    • Part Number: PS-105R / PS-120R / PS-150R / PS-200R
    • Ports: 1x ⅛″ NPT male
    • Pressure Range:
      Part # Turn-Off Pressure Restart Pressure
      PS-105R 105 PSI 85 PSI
      PS-120R 120 PSI 90 PSI
      PS-150R 150 PSI 110 PSI
      PS-200R 200 PSI 165 PSI
    • Voltage: 12 Volts DC
    • Max Amps: 40 Amps
    • Length: 4.25″ (107.95 mm)
    • Width: 2.25″ (57.15 mm)
    • Weight: 1 lb (0.45 Kg)
    • Money-Back Guarantee/Refund Policy
      All merchandise unless otherwise indicated may be returned within 30 days from the shipment arrival date for a refund. A Returned Merchandise Authorization (RMA) number is required for all returns. A 15% restocking fee may apply. Additional deductions may be made to reflect the products current market value. These terms apply to all refunds. Most products are shipped with a refund/replacement guarantee period unless otherwise noted in the product listing. Customers must inform of any order discrepancy within 7 days from the invoice date so that we may investigate and resolve the situation accordingly.
    • Warranty
      This product is backed by Viair's one-year manufacturer's defect warranty!
    • Satisfaction Guarantee offers our customers a 30-day satisfaction replacement or refund guarantee on all purchases, except when otherwise noted in the product listing.
    • Cross-Shipments will not cross-ship returned merchandise.
    • Physical Damage Policy
      Physical damage to any product purchased at will effectively void warranty coverage. Physical damage includes but is not limited to improper handling and/or any other type of damage sustained by irregular usage.

    Warnings & Notices

    Safety warning icon

    This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to

    Customer Reviews

    4.9 Based on 29 Reviews
    5 ★
    4 ★
    3 ★
    2 ★
    1 ★
    Customer Photos
    Write a Review Ask a Question

    Thank you for submitting a review!

    Your input is very much appreciated. Share it with your friends so they can enjoy it too!

    Filter Reviews:


    Great all the parts fit right and we're great to dealing with you guys the only thing is I wish you would make hoodies with the big truck on it

    Brandon O.
    United States United States

    Perfect service

    Great c/s Great products

    Frederick D.
    United States United States

    Horn blaster

    Five star products!! Quick shipping great great!! My wife drives my truck and let’s people know when they make dumb driving moves! Train horns are the BEST!!!

    HornBlasters Viair 165-200 PSI Pressure Switch with 40A Relay Review
    Shannon F.
    United States United States

    Worked great with correct part

    We ordered the horns and they were delivered remarkably fast. But when we installed we couldn’t figure out why they weren’t working. Once we received the correct pressure switch and finally had time to make the change the horns are literally a blast… lol

    Robert S.
    United States United States

    Works as it should for years.

    I've had a hornblasters kit since 2008. I've only had to replace two of these since. They reliably work for years under harsh conditions (under a truck)

    English en