Fixing a compressor switch

Got a problem with your air compressor ON OFF switch? Interested in learning a bit about fixing a compressor switch?

This is page two of information. Page one about fixing a compressor switch is here.

If you are just trying to find one here are some ON/OFF switches.

On the previous page we talked about determining if it was the ON OFF switch that had failed and was preventing the air compressor from starting, and how to test for that. We also discussed how to remove the exisiting compressor ON OFF switch

Once we have the ON OFF switch out of the compressor housing

Air compressor on off switch

The photo above shows how simple this type of switch is. A simple toggle to move the points inside the switch from non-passing to passing (open or close) and two spade terminals on the back of the switch for the quick-connection of the wires inside the compressor housing. That’s it.

As a result, you really will not be fixing a compressor switch so much as acquiring a working replacement.

These switches, we expect, cost the manufacturer a few cents to make. They will cost you a couple of dollars to buy. Spending time to try and disassemble and fix a compressor switch would not be cost or time effective.

So, now with  switch in hand we either find and purchase a replacement on line, or head off to a local electronics type shop where a replacement switch can be acquired for just a few dollars. Odds are very good you will find an exact replacement.

Then, with the new switch it’s but a few minutes work to pop it into the shroud opening, hold the shroud over the compressor to allow us to push the two wires onto the spade terminals (it doesn’t matter which wire goes on which side except that your ON may become OFF or the opposite if you reverse the wires), to reattach the housing, and then the air compressor, with its fixed broken compressor ON OFF switch, is back in business.

Help – I can’t find the right switch

The compressor ON OFF switch shown on these pages is a common one. If yours is not, don’t panic.

Most of the air compressor ON OFF switches are single pole, rocker style –¬† two-position switches. Either they are passing electricity (the switch is ON or closed) or they are non-passing (the switch is OFF or open).

Selection of rocker and toggle switches

In just a few minutes on line we found dozens of suppliers of these types of switches. The rocker and toggle switch images above, from left to right, are courtesy of:


There are a thousand and one styles and shapes and sources for simple rocker or toggle switches. Simply get one that is close to the size you need, and modify either the housing or the switch to fit!

As long as no wires are exposed, use any switch you like. Close counts when it comes to getting a replacement switch.

But do you need the ON OFF switch at all?

If your air compressor has a pressure switch that turns your air compressor on and off based on the tank pressure levels, then the compressor ON OFF switch is redundant, and is simply there for folks that don’t want to remove the plug from the wall socket to entirely shut down the air compressor.\

Inside the small air compressor

The two wires inside the white circle in the photo above are connected to the compressor ON OFF switch. One of these wires comes from the pressure switch and the other goes to the motor circuit. If we simply cut the terminals off these two wires and connected them together, we would have completely bypassed the ON OFF switch. Now, the compressor would turn on and off based on the pressure in the tank, and as long as the air compressor was plugged in, it would cycle on its own, based on the cut in and cut out pressure settings of the pressure switch.

however, if you leave an air compressor powered up, and you have a leak in the plumbing or a tank check valve that leaks a bit, then your air compressor will cycle ON and OFF as the pressure in the tank fluctuates. Trust me. Having an air compressor fire up in the basement in the middle of the night, scaring the spouse awake, is NOT a good thing! If you want to be sure your air compressor stays off, remove the power source by unplugging the air compressor or, if the ON/OFF switch works, shut the switch off.

My Pressure Switch has my compressor ON OFF switch

Some air compressors are equipped with a pressure switch that has a ON / OFF switch as part of it, one of which, manfuactured by Lefoo, you can see below.

Lefoo compressor pressure switch

Other types of pressure switches may have a toggle switch on one side of them.

If your compressor ON OFF switch is part of the air compressor pressure switch, then, and depending on the complexity of the switch arrangement, your only option may be to replace the pressure switch with a similar model.

Yes, you can disassemble, maybe find parts, and then try to figure out how to reassemble the pressure switch with all of the springs and components that are part of it, or, you can replace it.

Depending on the type of air compressor you have, the pressure switch may cost from $20 – $40 or so. We have heard from many visitors asking for help in reassembling a pressure switch that they have, for a number of reasons, disassembled. That’s too much work and time for us, so we recommend that you get a new one for a quick fix of your air compressors broken ON / OFF switch.



  1. Hi, I’ve got a single cylinder Harbor freight compressor that won’t start. When I release the button on top of the pressure switch (with the tank empty) there is power on the motor side. Depressing the switch cuts the power. However, the motor doesn’t start, and shows no sign of drawing current. I pulled the compressor from the tank to check the wiring, and while re-installing it heard a distinct “pop”. The compressor then started. Now it’s failed again, and no amount of taping on the valve and compressor will re-start it. Any ideas?

    Thank you in advance.

    • We wish we’d heard the pop too, David. Our guess, it’s the start capacitor that’s failed and the pop you heard may have been it releasing power, but insufficiently to boost the motor to start. Please see the page on testing the capacitor, and do let us know if that’s nailed the compressor problem or not.

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