The heater is connected by two wires. Label the wires and connections
so that you can properly reconnect them later. The wires are connected with slip
on connectors. Firmly pull the connectors off of the terminals (do not pull on
the wire itself). You may need to use a pair of needle-nose pliers to remove the
connectors. Inspect the connectors and the terminals for corrosion. If either
is corroded they should be cleaned or 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. If the reading is not between those two extremes the heating element should be replaced.