Subaru DL A/C Compressor Cut-Off Switch Guide for 1979-1987 Models
If your Subaru DL's air conditioning has quit, this simple switch could be the reason.
- The A/C cut-off switch is a safety device to protect your compressor; its failure is a common reason for the A/C to stop working.
- For a 1979-1987 Subaru DL, a new aftermarket switch from Global Parts is the only practical new option as OEM parts are no longer made.
- Always verify the A/C system is properly charged with refrigerant and has no leaks before replacing the switch.
- Replacing the switch requires the A/C system to be professionally evacuated and recharged.
Is Your Subaru DL's A/C Blowing Warm?
For a vehicle from the 1979-1987 model years, a non-working air conditioner is common. If you've already checked the refrigerant level and fuses, a faulty A/C compressor cut-off switch is a likely and inexpensive part to investigate. When this switch fails, it can prevent the A/C compressor from turning on at all, leaving you with nothing but warm air from the vents.
Symptoms of a Failing A/C Cut-Off Switch
- A/C System Won't Turn On: The most common symptom is an A/C system that does nothing when you press the button. The switch is failing to send power to the compressor.
- Only Warm Air Blows: If the compressor isn't engaging, the refrigerant isn't circulating. The result is that the air from the vents will never get cold.
- Intermittent Cooling: The switch might be failing intermittently, causing the compressor to cycle on and off rapidly. You might get short bursts of cool air, or the cooling may come and go as you drive.
- Clicking Noises: You may hear the A/C compressor clutch trying to engage but immediately clicking off. This can be a sign the switch is cutting power due to a pressure issue or its own failure.
A Note on Refrigerant
Your 1979-1987 Subaru DL originally used R12 refrigerant, which is no longer available to the public. Most systems have either been converted to R134a or another alternative. A low refrigerant level is the most common cause of A/C issues and will also cause the cut-off switch to keep the compressor off. Always have your system's pressure checked before replacing parts.
Choosing the Right Aftermarket Part
For a vintage vehicle like the Subaru DL, finding original equipment (OEM) parts is nearly impossible. They are considered "No Longer Available" (NLA) from the manufacturer. This leaves two options: a used part from a salvage yard or a new aftermarket part.
Global Parts is a well-known aftermarket manufacturer of A/C components. While aftermarket parts for older vehicles can be a mixed bag, the reality is that for a simple electronic switch, a new aftermarket part is often the most practical and reliable choice. A new Global Parts switch has a higher chance of working correctly out of the box compared to a 40-year-old used switch with an unknown history. Given the low cost, it's a sensible repair for getting an older A/C system functional again.
Cost to Replace Subaru DL A/C Cut-Off Switch
| Part Type | Part Cost | Labor Cost | Total Cost |
|---|---|---|---|
| New Aftermarket (Global Parts) | $9.01 | $70 - $150 | $79 - $159 |
| New OEM | Not Available | - | - |
| Used OEM | $5 - $25 (if found) | $70 - $150 | $75 - $175 |
Note: Labor costs are estimates and do not include the price of evacuating and recharging the A/C system, which is a necessary step.
Pro Tip: Check for Leaks First
The cut-off switch is doing its job if it prevents the compressor from running due to low refrigerant. Before replacing the switch, have a mechanic check the system for leaks. The most common leak points on older Subarus are the O-rings where hoses connect. Fixing a leak and recharging the system may be all you need.
Frequently Asked Questions
Where is the A/C cut-off switch located on a 1979-1987 Subaru DL?
Based on owner forums for similar models, the pressure switch is typically located in the engine bay on the passenger side. Look for it on the A/C lines near the receiver/drier (a black cylindrical canister), often situated down behind the passenger-side headlight. It will have a small electrical connector attached to it.
Do I have to empty the A/C system to replace this switch?
Yes. The switch is threaded into a pressurized A/C line. Attempting to remove it without properly evacuating the refrigerant first will result in a rapid, dangerous release of refrigerant and oil. This job requires special equipment, and it's recommended to have a professional shop evacuate the system before you replace the part, and then recharge it after.
Is an OEM switch better than the aftermarket Global Parts switch?
While OEM parts are usually the benchmark, they are not available for this vehicle. A new aftermarket switch from a brand like Global Parts is a better choice than a used OEM switch of questionable age and condition. For a simple, low-cost part, the new aftermarket option is the most logical path to repair.
Why isn't my A/C working after replacing the switch?
If a new switch doesn't solve the problem, the issue lies elsewhere. The most likely cause is a leak that has allowed the refrigerant to escape. Other possibilities include a failed A/C compressor clutch, a bad relay, a blockage in the system, or issues with the expansion valve. A full system diagnosis by a qualified mechanic is the next step.
Technical Specifications
This is a pressure-activated electrical switch designed to work with the vehicle's specific A/C system pressures.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.