where are the fuses i need to check on my 98 sts cad with regard to brake lights

First, make sure the bulb is good as the element may even look okay, but it still might not light up. If they are double filament bulbs, they should share a fuse.
However, the fuse box for the brake lights is located under the left rear seat. I have included a diagram showing its location.

Thanks, all the fuses were good, but as I was working on it my neighbor came by and wriggled the bulb around until the second filament lit up, then after about 5 tries, he lifted the wires on the new bulb a little bit and that did it! Brake lights!!!
Thank you for responding. Got it fixed before I read my email.

You are very welcome and I am glad to hear that it turned out to be an easy fix.
If you ever need anything in the future, we are always glad to help.

Take Care

Dr. C

Now I need to check the fuse on the CHMSL....?

It should be located in the right front corner of the engine compartment, near underhood fuse block.
It has a black, 3 pin connector.
I could not find the information on it to answer your question. So, I would recomend checking it. I only had the location information.