Check out this post from TBone1964 that shows a schematic of the full gauge cluster circuit. You'll notice that the temp light is not connected to anything when you've got a temperature gauge. There is no wire installed in pin 5 of the gauge cluster connector.
http://67-72chevytrucks.com/vboard/s...70&postcount=2
This means your current issue is limited to a nonfunctional brake warn light. Here's what I would check:
1) Power for the brake warn light comes from the pink wire on pin 3 of the gauge cluster connector, which I believe is fed by the Cluster Feed fuse on the fuse panel. You replaced the fuse already. Is the new fuse still good? Use a multimeter to check for 12V on the pink wire on the gauge cluster connector.
2) Remove the brake warn light bulb and check for 12V on one side of the contact on the flexible circuit board for the bulb. Sometimes the circuit board connections get corroded and need to be cleaned up with fine sand paper or Scotchbrite.
3) With the bulb still removed, check for continuity between the ground terminal for the bulb on the circuit board (the one that didn't have 12V on it from the previous test) to the terminal on your ignition switch that has two tan wires running to it.
4) When you turn your ignition switch to the starting position, do the two tan wires on your ignition switch connect to ground? Check this with your battery disconnected so you don't have to deal with your engine starting up. Check for continuity from the tan wires to the metal of the dash with the key in the cranking position.