enter image description hereinstalling fan and light kit Issue: have 2 white wires and 2 black wires in ceiling box .Both black wires always have power Neither white wire has power whether the wall switch is on or off . The wall switch has white wires on both terminals and looks like black wires pigtailed behind, cannot get light to work from switch only will work with pull chain, fan works fine.
OK, the switch in the wall is just sloppy work someone pigtailed the switch and they just used white instead of a correct color.
That gets us to the fan junction box. If you don't know, you need to find the black wire that is controlled by the switch. simply turn off the switch and put you meter on the black wires, at least one of them should show no power. Verify by turning on the switch and it should now read 120V. Mark that wire as your switch leg. If the other black wire is continually on just leave it alone. The white wires are your neutral. Kill all power to the junction box.
Your fan should have four wires green (ground), White (neutral), Black and it should be labeled "fan", and blue or red and should be labeled "light". Of course you need to mount your hanger. Then connect your green wire first to the other ground wires or a ground screw. Then connect your white to your other white wires. Then connect your blue and black wire from the fan to the switch leg and button up the junction box making sure no wire are pinched and hang you fan motor.
When you attach your light kit to you fan you will see a multiple pin connector coming down from the fan. When you look at your light kit you will find a matching pin connector. Plug those connectors together and make sure they are locked in place. All you have to do know is hook up you light kit to the fan.
The switch in the wall should power up both the fan and the light kit. Both the fan and the light kit can be controlled by the pull switches on both devices.
Whew. Good luck