Only available to me is the 1994, therefore you need to check if your 1991 is the same. I would guess that it is at least similar but YOU have to make sure.

 

the rear struts act as the + and - for the defogger. This can cause more issues. The negative (ground) may be conductive everywhere, while the positive needs to be insulated towards the body, else it will short out.

Actually the strut is just an elegant way to connect the heating grid to the power and ground through the struts. It should be possible to fix it by soldering a wire to the remainders of the broken off connector. Or as you suggest having a cable run directly from the connector (female) to the grid but then when closing the window you need to take care of where that cable goes.

BTW. Greetings from Switzerland.
Yeah, shipping oversee is sometimes more expensive than the parts themselves.

Merry X-Mas

 

Great and Thank you for the wiring diagram.
at first sight it seems to be the same as a 1991 model (they are almost the same)
i can not thank you enough for this information.

ps: my 1991 s10 blazer is imported from st-moritz Switzerland

Greetings from Belgium and merry x-mas and a happy new year