Fixing a compressor switch

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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 existing 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:

  • https://www.aliexpress.com
  • https://www.phaseda.com
  • https://www.motorsport-tools.com

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.

By Ashley Pearce

As a passionate manufacturing and mechanical engineer, I've had my fair share of run ins with air compressors and compressed air systems. With over a decade of experience in the industry, I have both a fresh perspective and time-served hands and mind to help you with your compressor problems (along with our able community!)

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Tony Maples
Tony Maples
October 15, 2019 11:43 pm

I have an Lefoo LF10-4h. How do I reassemble it? I took it apart to move the ports, I guess that what you call them and I have no idea how it goes back together. I have looked online with no luck. I can’t find one like that online either. Its going on a central pneumatic air compressor. 21 Gallon. Please help me cause I am lost.

Fix My Compressor Moderator
Fix My Compressor Moderator
Reply to  Tony Maples
October 16, 2019 8:05 am

Are you asking about rebuilding the switch, as in you have completely taken it apart, or reattaching the Lefoo to the compressor? Please clarify. The troubleshooting page has links to how to reassemble a pressure switch if that’s the information you are after.

Tony Maples
Tony Maples
Reply to  Fix My Compressor Moderator
October 16, 2019 11:07 am

Thank you. Where exactly is that troubleshooting page?

Fix My Compressor Moderator
Fix My Compressor Moderator
Reply to  Tony Maples
October 16, 2019 12:28 pm
Tony Maples
Tony Maples
Reply to  Fix My Compressor Moderator
October 20, 2019 1:40 pm

Not sure what you sent me, but I dont see anything on that page telling me how to rebuild it. Thanks anyway

ryan hahn
ryan hahn
August 19, 2019 12:10 am

How do I hard wire my air compressor and eliminate the fuse

Fix My Compressor Moderator
Fix My Compressor Moderator
Reply to  ryan hahn
August 19, 2019 9:08 am

You don’t. If the fuse keeps blowing, fix the compressor. If you hard wire the compressor without fixing the problem you will burn out the motor.

Sigmond J Williams
Sigmond J Williams
March 27, 2019 5:11 pm

I have a Porter Cable C2002 Type 7 1 HP 6 Gallon Compressor. I installed a new pressure switch. The compressor runs for a few minutes and died again. Is there anything that may cause the switch to burn out. I did smell an electric burning smell. I don’t want to try another switch before making sure. Thanks for any info to help me with the issue, Sig.

Fix My Compressor Moderator
Fix My Compressor Moderator
Reply to  Sigmond J Williams
March 27, 2019 5:59 pm

How did you determine that it was the new switch at fault, Sig? If you have a meter, check the power on the motor side of the switch with the compressor on and the tank empty. Power should be flowing. Please advise.

David
David
June 6, 2016 3:00 pm

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.

Fix My Compressor Moderator
Fix My Compressor Moderator
Reply to  David
June 6, 2016 5:07 pm

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.