How to check Some compressors have a black plastic overload under the compressor cap which could be bad.

You should check if the compressor is running. Your description makes it appear that the fan may be running and the compressor may not be running.

There are many things that can cause a compressor to cease running:

Open defrost thermostat
Bad run capacitor
Low refrigerant charge (caused by refrigerant leak)
Bad compressor relay
Bad compressor overload
Bad compressor motor

Other things to check:

If the fan switch is set to "on" and the humidity control is set to a high humidity level, the unit may appear to be running, but the compressor will not operate. Check the setting of your humidity control.

If the dehumidifier is operating in a room with a high temperature and a low dew point (very low relative humidity), it may be unable to remove any more moisture from the air.

If you are not comfortable troubleshooting the unit on your own, call the manufacturer service department at 1-800-533-7533, EXT 8459. They are very helpful.

The black cylinder is the compressor. It sounds like your unit is cycling the compressor for some reason. If the compressor starts, runs fine, and removes water when you set the humidity control to the driest setting the compressor is probably OK and the problem may be with the humidity control causing the dehumidifier to "short cycle" for some reason. You may need to change the humidity control or relocate the dehumidifier in your crawl space.
If the compressor attempts to start, and then sits quiet for 10 minutes, and then attempts to start again, you have a problem with the dehumidifier. There are a few things that can cause this problem:
Low refrigerant charge
Bad compressor capacitor
Bad compressor overload
Plugged capillary tube or broken expansion valve
are the common causes of this behavior. If you suspect one of these problems, call the factory service department at 1-800-533-7533 for help.

Good luck with your dehumidiifer.

the compressor has an internal overload to protect it from overheating. the compressor is cooled by the refrigerant passing over it. It could be a bad compressor,, bad charge of refrigerant, or simply dirty coils not allowing air movement

i would do a continutity check on you relay and overload, other than that
what is the humidity level in the room, as well as the ambiant temp. these mahines cycle for that very reason, the fan will come on, do a check and then determine if it should start the compressor.
check if you have voltage at the compressor when its supposed to be running ( just a last thought)
ive seen compressors ohm out, but in fact be bad

Compressor won’t Start
The Main reasons that this will happen
1 - A bad run capacitor (silver or metal capacitor)
It’s either shorted, grounded or open.
If it’s shorted a lot of times it will bulge out, (sometimes slightly)
2 - A bad start kit ( plastic capacitor and Relay connected to it )
The capacitor is either shorted or open
The relay either has an open coil between terminals #1 and #5
Or the relay is stuck.
Any time you change the capacitor or relay you should change
the other, especially if they are over a year old.
3 - A loose, burnt or disconnected wire
4 - Wired wrong
5 Compressor is open (windings burnt open)
6 Low on charge not getting enough cooling back to compressor, (Feel top of compressor to see if it’s hot it shouldn‘t be)
7 Some compressors have a black plastic overload under the compressor cap which could be bad.

The Main reasons that this will happen
1 - A bad run capacitor (silver or metal capacitor)
It’s either shorted, grounded or open.
If it’s shorted a lot of times it will bulge out, (sometimes slightly)
2 - A bad start kit ( plastic capacitor and Relay connected to it )
The capacitor is either shorted or open
The relay either has an open coil between terminals #1 and #5
Or the relay is stuck.
Any time you change the capacitor or relay you should change
the other, especially if they are over a year old.
3 - A loose, burnt or disconnected wire
4 - Wired wrong
5 Compressor is open (windings burnt open)
6 Low on charge not getting enough cooling back to compressor, (Feel top of compressor to see if it’s hot it shouldn‘t be)
7 Some compressors have a black plastic overload under the compressor cap which could be bad.

The Main reasons that this will happen
1 - A bad run capacitor (silver or metal capacitor)
It’s either shorted, grounded or open.
If it’s shorted a lot of times it will bulge out, (sometimes slightly)
2 - A bad start kit ( plastic capacitor and Relay connected to it )
The capacitor is either shorted or open
The relay either has an open coil between terminals #1 and #5
Or the relay is stuck.
Any time you change the capacitor or relay you should change
the other, especially if they are over a year old.
3 - A loose, burnt or disconnected wire
4 - Wired wrong
5 Compressor is open (windings burnt open)
6 Low on charge not getting enough cooling back to compressor, (Feel top of compressor to see if it’s hot it shouldn‘t be)
7 Some compressors have a black plastic overload under the compressor cap which could be bad.

The Main reasons that this will happen
1 - A bad run capacitor (silver or metal capacitor)
It’s either shorted, grounded or open.
If it’s shorted a lot of times it will bulge out, (sometimes slightly)
2 - A bad start kit ( plastic capacitor and Relay connected to it )
The capacitor is either shorted or open
The relay either has an open coil between terminals #1 and #5
Or the relay is stuck.
Any time you change the capacitor or relay you should change
the other, especially if they are over a year old.
3 - A loose, burnt or disconnected wire
4 - Wired wrong
5 Compressor is open (windings burnt open)
6 Low on charge not getting enough cooling back to compressor, (Feel top of compressor to see if it’s hot it shouldn‘t be)
7 Some compressors have a black plastic overload under the compressor cap which could be bad.

My Kenmore had the problem of the fan running, but not the compressor. The compressor overload part was bad.

Togarba

Lifeguard, there are generally no user accessible safety items in dehumidifiers. You are likely describing the start relay which is used to 'boost' the compressor on starting. Jumping it will not help you. It sounds like the compressor is defective. Economically, there is no justification for servicing these units unless they require refrigerant gas or if the fan motor has seized, something you can readily determine. If you don't hear the compressor hum when it should, there is no service procedure available for these sealed units.