How to replace an unloader solenoid - air compressor bleeding air, not building pressure

This video shows how to troubleshoot and replace a bad unloader solenoid (similar to an unloader valve) on a GMC/California Air Tools compressor.

The symptom of a bad unloader is the sound of air rushing out while the compressor is pumping, and pressure is not building in the tank. This is because the unloader solenoid that should be closed during pumping is burned out, and the unloader valve keeps bleeding pressure that should be going into the tank.

It's easy to obtain the solenoid from the manufacturer, but not so easy to replace the whole unit due to space constraints, so I show a little trick of only replacing the solenoid winding and leaving the rest of the valve in place.

Note: it's unusual for the unloader to be a solenoid. The more normal setup is a mechanical unloader valve. See my related video for an explanation of its operation, along with an explanation of each of the compressor's parts and their function.