I have a retractible antenna that has been broken,it works on a up and down switch. It got broken at a car wash. Is the part still available and is replaceing it a tough job.

You can buy a replacement for your Marquis mast on eBay. I have not seen these offered by NAPA, O'Reilly, AutoZone, etc.

http://compare.ebay.com/like/160344383074?ltyp=AllFixedPriceItemTypes&var=sbar

You could try searching for a used antenna on www.car-part.com.

Removing the antenna mast is easy once the collar nut is removed. Try tapping a screwdriver in one of the two slots with a hammer counter-clockwise, gently, until it loosens. Be careful not to chisel your painted fender. Once the nut is off, you can manually pull it out or power it out with the antenna switch with a helper holding the antenna mast so it doesn't flop onto your fender.

To install it,have a helper hold the 'down' button and feed the white nylon end into the hole. If it doesn't catch, rotate the nylon part clockwise in the hole and hold downward pressure on it until the motor gear catches the nylon piece. After the entire antenna has retracted into the fender, replace the nut.

Here is a video:

http://www.youtube.com/watch?v=nEJtooskd9Y&feature=related

It's a Honda, but it's the same deal.