When the zipper on my awning failed, the dealer told me they had to ship
the whole awning back to Coleman/Fleetwood, where they would put the
awning into a new bag, and return it.  Sounds kind of dopey, but that's
what they did.  I guess the awning has to be attached to the bag.

Unless you can land yourself a seamstress or upholsterer who could maybe
replace the zipper for you, I'd contact the nearest dealer who sells
Fleetwood popups and ask them...it has to come up all the time because
IMHO the zipper on the bag is an undersized POS.

We took our '97 Cheyenne awning to a automotive upholstery shop
to have the zipper replaced.  BTW, if you remove one of the end
caps on outer support bar, you can slide it off just like you do
on the trailer end.  Now it is flexible and can be put in a car.
It wasn't long after the zipper job that the thread to the
plastic bead on the bag end started breaking.  You might want to
have it re-done while you are at it.