Lower Relay Board 318022001

Frigidaire gallery double oven model pleb30t8acb mfg august 2002 re no heat from bake element in lower oven. upper oven and all other functions work fine. on turkey day my wife turned on the lower oven to preheat and after an exceptionally long time it still hadn't reached temperature. i looked it over and noticed the lower element wasn't hot at all. i played around awhile and could hear the relays click, the upper element would come on and it displayed preheat when i'd set a much higher demand temperature. i decreased the temperature to a few degrees above the oven temp and saw the indicator calling for heat and heard a relay click but still nothing in terms of heat from the bottom element. even when i tried a cleaning cycle only the top element came on. convection fan works, cleaning lock works, light too! i ordered a new element, tested it to 21ish ohms. i removed the old element and it too read 21ish ohms. it appears it's not the element but i installed the new one regardless and no change. i see the diagrams for an upper oven relay board and a lower oven relay board. both are pricey (>$200). if i could be sure it was just the lower oven relay board i'd replace it but thought i'd ask here first before becoming an expensive part swapper. how do i remove and test the lower oven relay? is there something else i should check?