the antenna on my C5 (2000) convertible stopped going down without manual help. It came up fine but wouldn't go down. Using some excellent resources on this Forum, I attempted to pull out the mast and replace it with no luck. I then took out the motor, again using some excellent resources on this Forum. The nylon cord was broken off in the motor. After removing the broken piece, I reinstalled the motor, which no longer worked...nothing happened when I hit the power button. I traced power into the unit, so I knew it was getting power but refused to work. So now the search for a replacement motor. As most of you know the original motor (which was made by Harada) is no longer available except from salvage at incredible prices. However, I was able to get Metra Electronics 44-PW22 to work with some "fitment" issues. (also available with a black tip). I won't cover the removal since that is thoroughly covered by other Posts in both the C5 Tech and C5 General forums. Following are the mods I made to 44-PW22 to make it work. BTW: huge shout out to the tech help line at Metra. He was exceptionally helpful. Also, thanks to the engineer at The Antenna Source for a thorough explanation of the issue and history of the antenna motor issue.
1. Antenna Cable: the original antenna cable terminates in a female. The Metra terminates in a male. Buy Metra adapter 40-UV41.
2. Motor wiring: The original unit has a specific connector to mate to the car wiring. The Metra unit has spade ends. Cut the end off of the original unit and connect it to the Metra unit.
3. Mounting bracket: The Metra unit will mount to the original Harada bracket with a slight carve-out on the bottom to accommodate the drain hole on the Metra. However, the bracket will not then mount to the wall. Use the mounting strip from the Metra unit to accommodate the difference.
4. Install: you may need to slide the power connection on the mast around until you find the perfect fit. Attach the top nut, hit the radio, crank up ZZ Top, and hit the road!

after removing the motor, I detached the mast tube and forced the mast out of the tube

part of the antenna nylon cable was broken off inside, requiring a removal of the cover.

the original unit wiring has a plug that matches to this female on the car.

remove this male plug from the original and use butt connectors to attach it to the Metra unit. Metra (M) Red to Corvette (C) orange. M Black to C Black. M Blue to C Green. This got a little confusing for me, so I diagrammed it out to make sure I got it right. Thanks to the Metra tech guy for leading me through it.

mount the Metra unit to the original Harada bracket. The Metra unit mounts to the plate; however, you may need to cut out a small section to accommodate the drain hole on the Metra. The Metra sits on the bracket differently than the original unit, which won't allow it to fit to the bolts on the trunk liner. I used the mounting strips from the Metra package to make it fit.

antenna now goes up and down smoothly.