Does your air compressor have a broken compressor ON OFF switch? Here is what you can do about it.
The air compressor that you purchase for under $250 may not be manufactured with the best quality parts, and that, unfortunately, includes the ON OFF switch. The vibration from the air compressor running may loosen a wire, frequent cycling of the switch may break an inner component, or the switch may be broken by something impacting it from the outside.
How do you know you have a broken compressor ON OFF switch?
How do you know you have a broken compressor ON OFF switch, one of which is shown in the photo below? This switch is recessed inside the housing on this spiffy little Campbell Hausfeld air compressor, the location shown inside the white circle in the photo.
If your compressor ON OFF switch is broken, the most obvious symptom is that your air compressor will not start.
A broken ON OFF switch is not the only thing that will prevent your air compressor from starting. To weed out a few of the other reasons, make sure that you have power at the plug where you plug the compressor in (plug something else in and ensure that it runs), and also open the tank drain and bleed out all the air that may be in the tank. If it’s been a while since you did this, then you’ll get a lot of water coming out with the air. That’s normal, and messy! See the tank drain on the compressor above, the little brass protrusion on the left bottom of the air tank. When you are done draining the tank, close the drain.
With the tank empty of air and being sure that there is power to the compressor plug (meaning power flowing down the compressor power cord to the air compressor), flip the compressor ON OFF switch to ON again. If the compressor starts now, it is almost certain that your ON OFF switch IS NOT the problem.
If your air compressor still does not start, then it could be the ON OFF switch, or it still could be other issues.
Time for a multi-meter check
If the compressor has a broken ON OFF switch that prevents power from getting to the motor circuit, then logically power can not be passing through the switch when it’s turned on. This you need to check with a multi-meter.
To test the switch with a meter, you will unplug the compressor again, remove the housing or panel on which the ON OFF switch is located, a carefully invert the cover as far as it will go to expose the the switch terminals inside the cover, in a similar fashion to that shown in the photo below. It is useful when attempting this check to have either a third arm, or a helper.
Ensure that the compressor switch is in the on postion, and plug the air compressor into the wall socket. Use the probe on the multi-meter to first check that power is getting to the switch (this confirms there is no break in the power cord) and then probe the motor side of the switch to test for power coming across the switch.
If there is no power on the motor side of the switch, and for sure the switch is on and power is on the supply side of the switch, then this compressor ON OFF switch is toast!
Time to change it, unless you are one of those folks that loves to torture themselves. If so, open the switch up and try to fix it. This is not something we would try to do, as replacement switches are cheap and our time is not.
Here is a selection of some ON/OFF switches for your review.
Change a broken compressor ON OFF switch
The ON OFF switch on your smaller air compressor is likely to be on your air compressor housing or panel, as is ours.
In the image below we have already removed the wires from the switch inside, and then popped the ON OFF switch up and out of the shroud housing. This switch is pretty easy to remove, with its friction tab that you depress to allow the switch body to clear the edge and to be removed from the housing opening. You can see that tab on the end of the switch closest to you in the photo below.
After you have ensured that the compressor power cord is unplugged and opened the tank drain or used the compressor PRV to dump all the air from the compressor you will have to remove the compressor housing or air compressor control panel to access your switch connection.That process might be easy or complex, depending on the type of air compressor you have.
We were fortunate that the shroud on our test compressor required the removal of just four bolts to enable us to lift the shroud from the compressor, and to see the switch wires attached to the spade terminals underneath the compressor ON OFF switch. It was only a moment or two to remove the two wires, and free the shroud and switch from the air compressor.