Not a huge deal. Same thing happened on my 1999. Plastic cogged drive cable broke at the very tip in the motor housing.
-source a new power antenna mast. I bought mine off ebay from a seller in Detroit
-remove plastic cap on the top of the fender around the base of the power antenna. It pops up. Put masking tape on the fender, then pry up with a small flathead screwdriver
-unscrew the large nut retaining the power antenna mast. If I remember correctly, the base does not need to be unbolted. Pull the mast out.
-transfer the mast retaining nut to the new mast
-remove passenger's side wheel and inner fender line. Not the splash shield, but the inner liner
-unplug electrical connection to the power antenna assembly. Factory service guide says you have to completely remove the antenna cable from the passenger compartment. I didn't, as there was plenty of slack for me to work on the motor in the wheel well
-unbolt the power antenna assembly from the body
-remove the plastic cover from the side of the assembly. The screws were quite tight on mine
-fish out the broken tip of the cogged drive cable. You can see how the cogged wheel engages the cable to run it in or out
-reassemble everything
-you will need a helper. Get the new mast ready, fully compressed. Turn the radio ON, wait until the power antenna motor stops turning. Feed the cable down the mast housing. When it bottoms out, you have to turn it to the left to get the cogs to engage. Turn the radio OFF. Feed the cable in as the cogged wheel pulls it in. Repeat until this works. It took me several tries. My wife was helping and not pleased.
-tighten the mast securing nut, reinstall the plastic cover
-lightly clean and lube the mast every oil change with WD-40 on a rag
Do a search, there are some good threads on mast replacement. The factory service manual has good instructions for it.
Good Luck!
Seth K. Pyle