The cabin blower for HVAC in my 99 f150 stopped working. The a/c/heat works, just will not blow out (unless the truck is moving). The auto repair place said it was my resistor, so I replace it with a new one. That didn't fix it. Now I'm told to replace the blower motor. Is it under the dash behind the glove box or the hood?
someone said to check the relay but I don't know where its at.

 

2003 F150 SC: blower motor is in the passengers floorboard area, just under (and behind) the glovebox. Your 1999 is likely the same.

I'm working through the same problem right now and have a new blower ordered. Did you check the fuses: one under the hood and one at the drivers side panel? Also, check the relay behind the dashboard near the cig lighter / powerport. You can temporarily cannibalize one of the relays from the drivers dash panel to rule of a relay problem.