NRF AC Pressure Switch 38939

An A/C compressor that won’t engage at all, or cycles on and off rapidly, often isn’t a compressor problem — it’s the pressure switch protecting the system by cutting power outside a safe operating range. The NRF 38939 is a direct-fit replacement.

Key Benefits

Here’s what this part brings to the job:

• 3/8-24UNF Male thread, matching the original switch’s mounting port
• 3-pin/connector electrical interface matching the factory harness
• Matched to the original part number rather than a universal or generic substitute
• Sourced from NRF, a supplier of automotive climate control and electrical components

What’s In The Box

• Brand: NRF
• Part / Model Number: 38939
• EAN/Barcode: 8718042060662
• Model: EASY FIT
• Number of pins: 3
• Thread Size: 3/8-24UNF Male

Because these parts are matched to exact electrical and (for pressure switches) thread specifications, always verify fitment using the EAN/barcode or part number above rather than the vehicle make and model alone — the same platform can ship from the factory with more than one configuration depending on trim level and production year. If you’re cross-shopping, our full AC pressure switch selection lets you compare specifications side by side before you commit to a part number.

Application & Use Case

The A/C pressure switch is threaded into the refrigerant circuit and monitors system pressure electrically, cutting power to the compressor clutch if pressure falls outside a safe range. Low pressure typically means the system is undercharged or leaking (running the compressor dry would damage it), while excessively high pressure can indicate a blocked condenser or an overcharged system. Either condition trips the switch as a protective measure. For background on where this part sits in the broader system, see how automotive A/C systems work.

A failing switch can either stick open (compressor never engages, no cold air at all) or stick closed (compressor runs even when it shouldn’t, risking damage from low-refrigerant operation), and corrosion at the electrical connector is a common non-mechanical cause of erratic operation. Confirm the 38939 matches your vehicle’s original part number, thread size, and pin count before ordering — pressure switches are not universal, and installing the wrong pressure rating can leave the compressor unprotected even if the switch physically threads in.

Installation Overview

Because the pressure switch is threaded directly into the refrigerant circuit, replacing it requires recovering the system charge first using certified recovery equipment — refrigerant can never be vented to the atmosphere, and under EPA Section 609 requirements, anyone servicing a motor vehicle A/C system for payment must be Section 609–certified and use approved recovery equipment. Once the system is depressurized, the old switch is unscrewed from its port and the electrical connector is disconnected, then the 38939 is installed with a new sealing washer or O-ring if one is included, torqued to the specification for that thread size. After installation, the system should be evacuated to pull a vacuum and check for leaks at the new switch before it’s recharged to the vehicle’s specified refrigerant weight.

Quality & Manufacturing Standards

NRF is a Dutch manufacturer founded in 1927 (a subsidiary of Modine Manufacturing since 1989) that specializes in engine cooling and climate control components for the automotive aftermarket. Component suppliers in this category typically manufacture under IATF 16949–aligned quality systems, the automotive industry’s standard for consistent, defect-controlled production — a framework that covers everything from raw material sourcing to final electrical testing before a part ships.

Shipping & Delivery

This part ships from our US warehouse network to all 50 states. Order processing and transit times are listed on our shipping policy. Every order includes tracking, and our contact team can help if you need it faster for a vehicle that’s currently off the road.

Support, Warranty & Returns

We stand behind what we sell: review our warranty policy and terms of service before you buy, browse our FAQ page for common fitment and shipping questions, or contact us directly if you have a question this listing doesn’t answer. You can also browse our full AC pressure switch selection to compare this part against other options for your vehicle. Learn more about how we source and vet the parts we carry on our about us page.

Frequently Asked Questions

Is this the correct pressure switch for my specific vehicle?

Match the part number, EAN, thread size, and pin count listed above against your vehicle’s original switch or service documentation. If you’re not sure, contact our team and we’ll help confirm fitment before you order.

Can I install this myself, or does it need a professional?

Replacing a pressure switch requires recovering and recharging refrigerant, which under EPA Section 609 requirements legally requires EPA Section 609 certification and approved recovery equipment if it’s done for payment. Many DIYers with the right certification and equipment can do this job; without it, this is a job for a licensed A/C shop.

Will replacing the switch fix my A/C compressor that won’t engage?

If the switch is stuck open or reading incorrectly due to a fault, yes. If the compressor won’t engage because the system is genuinely low on refrigerant or has a bad compressor clutch, replacing the switch alone won’t fix the underlying issue — a proper diagnosis before replacement helps confirm which component is at fault.

How does a pressure switch protect the compressor?

It monitors refrigerant pressure electrically and cuts power to the compressor clutch if pressure falls outside a safe range, preventing the compressor from running dry on low refrigerant or operating under dangerously high pressure from a blockage or overcharge.

Do I need to add refrigerant oil when I replace the switch?

A small amount of oil may be lost when the switch is removed, but the volume is generally negligible compared to hose or line replacement. Check your vehicle’s service procedure if you want to top off precisely.

How long does shipping take?

See our shipping policy for current delivery timing. We ship to all 50 US states.

What’s your return and warranty policy?

Full terms are posted on our warranty policy page. If a part arrives damaged or doesn’t match your order, contact our team and we’ll help sort out a replacement or return.

Is a core exchange required on this part?

No core exchange is required for this part — it ships as a standalone replacement unit.

What does “38939” mean on the box?

That’s the NRF part number for this exact part — 38939. Use it to cross-reference against your old part or your vehicle’s parts catalog to confirm you’re ordering the correct unit.