On an 1999 oldsmobile intrigue my tail lights and dashboard lights(only the rpm dial, mph, and lights for my A/C and heat) go out simultaneously. The funny thing is they work about 1/3 the time. What could be the problem?

Hello Alex.
The affected lights you are describing are on the same circuit from the fuse.
You will need to trace this circuit to find the intermittent open circuit.
I would start with the fuse. It may be cracked.
Also look at the terminals where the fuse goes in for corrosion.
You may end up tracing the harness for the problem if it isn't at the fuse box.
I doubt your light switch is the issue if your front park lights are working normally.
This could be a tricky one to find if the lights are working when you are looking for the problem.

I hope this guides you to a solution.

KL