Heater coil may be grounded. Check resistance between heater terminals and the heater metal case. What was resistance of heater coil across the terminals? What is model number of dryer?

Eric

As fairbank56 said a model number would be useful here as this is a weird problem.

If the element is not grounded.
Check for the 240 at the terminal strip with the element on and off.

If it also drops out when the heater should be on then it could be a bad power cord, wall receptacle or the circuit breaker.
Most likely the breaker.

Ok sorry it took so long. 12 hour shifts are brutal. Checked both coil leads to ground and got no continuity. I also checked the input 120v legs with the load attached and it was still 120v at each leg. I have no idea what model it is. It has a cycling thermostat, a high limit thermostat attached to the coils, a thermal cutoff switch above the high limit thermo, and a thermal fuse above the cycling thermostat. Hope that helps. Thanks again.

One other thing.
You said " I also checked the input 120v legs with the load attached and it was still 120v at each leg."

But did you get 240 volts between the two legs (L1 to L2) (red to black)?

Using Neutral/ground as a reference point in the heater circuit can be confusing as it is not part of the heater circuit.
The circuit is usually L1, a set of timer contacts , the thermal cut-off, the hi-limit thermostat , the cycling thermostat contacts , the heating coil , the heater centrifugal switch on the motor, L2.

What can happen if you use Neutral is that if one side of the line drops out then you see 120 everywhere as the good side of the line will feed through components and you have no way of knowing if you are reading L1 or L2.