Here are your parts, includes a wiring diagram.
Parts for FAM18EQ2A - AppliancePartsPros.com

Here is info on PTC heaters.
I would check it with a meter. Unfortunately I do not have info on what the resistances at different temperatures should be.
Start with a low meter scale and then increase it if you get infinite ohms.

If it has resistance then it could be the power relay (RLY3) is bad or the electronics that control the relay are bad.

If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.
4. When you start always short the meter leads together. This will tell you that the meter is working and if there is any 0 offset.

There is a good STICKY at the start of this forum about it's use.

If your thermostat has a switch to control the furnace fan, switch the fan "ON". Listen to hear the furnace fan coming on. If you cannot hear the fan, go to one of the supply registers and see if you can feel any air coming out. If the fan is not running, there may be no power to the furnace. If the thermostat is set properly, next step is to check to see that there is power to the furnace.Your heating system may be equipped with an emergency shut-off switch for the furnace. If your Air Conditioning System is so equipped, locate it and make sure it is turned on. Check to make sure all access doors are properly secured and fitted.