Bass Big Muff dry mode issue

[Darkmeteor]

Today I got a bass big muff in the mail, I bought it brand new online, and I think the pedal might be defective, the issue is that the dry mode works just like the normal mode, there is no dry signal..

So I was wondering if I'm doing something wrong or if it's something else, I have a gig on sunday so I was hoping maybe someone had a quick fix to get the dry signal to work, thanks