There is a wide range of products. This is correct.
Not " there are a wide.... Right?
At least I think so, but other native speakers seem to disagree.
Are both "is" and "are" acceptable in today's grammar?
When "is" is used, the focus is on there being a range.
When "are" is used, the focus is on there being products -- a wide range of them.
Thus, both forms can be correct. Which to use depends on the focus in context.