If you only have 2 wires/contacts the burner is intended for an 'infinite' or duty-cycle control. It will read mains voltage between phases, or zero. Must be best, it's what everybody eventually settled on.
They can still go wrong however. I've seen them fail to cycle and run at 'hi' setting regardless where the knob is. Bloody mess at best if you don't catch it, fire hazard at worst. Everybody breaks the rule "never leave cooking equipment unattended" and only get bit that one time in a buncha thousand.
Realizing this doesn't tell you what either Frigidaire is doing, but early GE/Hotpoint controls were:
HI--240V parallel both elements
MH--240V inner element only
M---240V series both elements
ML--120V parallel both elements
L---120V inner element only
SIM-120V series both elements
On HI both elements were equally red, but may still have been different resistances and lengths. I only have the single-coil/infinite model to look at now.
Nifty compact spaceheater below is 120V only, does the parallel/series thing for hi and lo, 1500/1200W. The 'nifty' parts are, it's barely bigger than your hand, and it's 25 years old and works like new. The company however, went out of business so you can't buy anything like it today. Note that the series is 20% below the parallel. But again, the coils are not necessarily equal resistance. They look different lengths and gauges.
