I have fixed the lugs on rear defroster setups at work.It is fixable,although its not easy.
I repair them at work with a good quality soldering iron.
I use a portable Snap-on one,but a good adjustable temp one from an electronics store will work.
BUT make sure that the temp is adjustable up to like 800 or so.
I know solder melts at a much lower temp,BUT you need that higher temp rating to get that large puddle of solder to gel.
First clean the points of contact and get a decent 60/40 rosin core solder to use.
Heres a link to a on-line soldering iron store for reference.
link
If money is tight the SP-80 will do,but if you can afford a lil more I'd suggest the
weller wlc100
Any more questions please feel free to PM me.