So I changed the heating element again. This time I put more solder on the joint. It is working now. I noticed that the last time the solder joints got hot enough to shrink the heat shrink. I'm thinking the original solder joints and my first attempt were poor, and broke after the unit heated up a few times. That's why people who had this problem got a temporary fix by jiggling the wires. I still haven't verified this with the meter on the old heaters to see if the are really dead.