Before you grab the pliers and end up damaging a zipper , try this -
Take a good size zip tie , loop it through the zipper pull and cinch it big enough to get 3 fingers in ... it will give you enough pull to get it zipped , and if it breaks , you need a warmer day or better fit possibly.
If you like it , you can super glue the zip tie in position and trim the excess.
It made a big difference on my Trektop NX rear zippers , which tend to be difficult.
Take a good size zip tie , loop it through the zipper pull and cinch it big enough to get 3 fingers in ... it will give you enough pull to get it zipped , and if it breaks , you need a warmer day or better fit possibly.
If you like it , you can super glue the zip tie in position and trim the excess.
It made a big difference on my Trektop NX rear zippers , which tend to be difficult.