Help:
I have an outdoor floodlight with indoor switch. Worked fine two weeks ago when I last used it. Not working now.
I have good power at the switch. At the fixture, I have very faint power. Any tips?
Late 60s home likely with aluminum wiring. Not sure what to call this, but the switch is the "in-line" type.
Any tips would be greatly appreciated.

You should be able to distinguish between copper wire and aluminum wire. Copper wire will be the color of a penny, aluminum will be the color of the top of a coke can. Aluminum wire is very soft and very subject to loose connections. Will also break very easily.

Check all connections. If that doesn't fix the problem remove switch. Temporarily connect the two wires together. Turn power on, if light burns replace switch. If light doesn't burn, repost starting your own thread. If you have aluminum wiring get proper connectors and add pigtails of copper wire to all switches and outlets through out your house.

Don't add a new question to an old thread.

I separated yours and started a new thread.

Define "good power at the switch".

Define "faint power at the fixture"

As HK stated, aluminum wire is easy to see, aluminum is sliver and copper is pink.

How about providing some pictures, esp on the "inline" switch.