A mounting assembly for supporting an LED in a lighting fixture. A first substrate containing the LED has contact pads in electrical communication with the LED. A contact carrier has a plurality of contacts that correspond with the contact pads of the first substrate. A second substrate has electronic components to power the LED. A first contact arrangement on the second substrate engages the integral electrical contact portions of the contact carrier, and a second contact arrangement provides external connections to the electronic components. A heat sink portion is engaged in thermal contact with the contact carrier and the first substrate. The heat sink portion includes finned members for dissipation of heat generated by the LED disposed within the heat sink portion. A slot is provided in the heat sink projecting axially of the heat sink portion, for receiving and securing the second substrate.