Why won't frost wire work?

Light fixture problem. I've read similar postings but still can't mine to work. Have a 3-wire cable and a 2-wire cable.

• Switch jct box has 2-wire feed's white connected with wire nut to white of outgoing 3-wire. Black feed wire connects to switch terminal, then to black of 3-wire cable. Red wire connects to other switch terminal. In the fixture jct box, black feed connects to black of 3-wire cable; whites of both cables are connected, along with white to fixture; and red is connected to black from fixture. I have a photo if that helps. I have a simple test light probe to check for power.

• Answer:

  I am thinking that the power is carried to either the switch box or to the fixture on the two wire; and then the three wire cable is used to carry both power and switch leg between the switch box and the fixture box. to troubleshoot: carefully use the probe to check for voltage betweent the (black) terminal of the switch and the ground wire. if that is good; then turn the switch on and check for power form the (red) terminal to the ground. if that is good, check the red at the light.if those are all good; backtrack, and check to make sure the connections of the white wires are secure; and you have power between black and white. hopefully, that will help you find the problem; and if not; I'll be back in tomorrow.