LED only works with halogen bulb

I have an under the counter fixture that has 2 12V 2 in halogen bulbs. I bought some round, disk type LED replacements(9 LEDs per disk). The LEDs themselves work. The fixture takes 2 bulbs. 2 halogens work. 1 halogen and 1 LED works. 1 halogen alone works. But neither 1 LED nor 2 LEDs (without halogens) works.



What can I look for to fix this

LED only works with halogen bulb