The heater is connected by two wires. The wires are connected with slip on connectors. Firmly pull the connectors off of the terminals (do not pull on the wire). You may need to use a pair of needle-nose pliers to remove the connectors. Inspect the connectors and the terminals for corrosion. If the connectors are corroded they should be replaced.
Test the heating element for continuity using a multitester. Set the multitester to the ohms setting X1. Place a probe on each terminal. The multitester should display a reading somewhere between zero and infinity. Because of the number of different elements we cannot tell what your reading should be, but we can be certain of what it shouldn't be. If the reading is zero or infinity the heating element is definitely bad and should be replaced.
You may get a reading between those extremes and the element may still be bad, you can only be certain if you know the correct rating of your element. If you can find the schematic, you may be able to determine the proper resistance rating. Also, inspect the element as it may be labeled.