When you create a sales funnel, it links all of the products in that funnel. If you find that your funnel is not working properly, there are a couple of things you can try to get things working correctly for you.
The first thing to remember is that the test purchase link completely ignores the sales funnel. If you use the product test purchase link, you will not be taken through the funnel you will be taken to the test link for that product, then sent back to your access page.
The best way to test out your funnel is to lower the price to $1 for each product, then just run through the entire funnel. The buy buttons from within the funnel are what controls the flow of customers through it. In order for the flow to work correctly, you will have to use the buy buttons from the funnel set up, rather than from the individual products. Your customers will be dropped from the funnel if you do not have the correct buttons set up.