Query A Table Using Multiple Values In Textbox On A Form - Not Working

I have a database in Microsoft access 2010. The database has a table that stores prospective customer records, and a form that is used to input a search criteria(s) via textboxes, which then queries prospective customers table and returns the records that contain the inputted search criteria(s).

An Example of Textboxes values on the search criteria form:
Textbox - name: bob
Textbox - address: Left blank
Textbox - category: car,boat,truck

I Have tried creating a query with the following

field: name
criteria: like “*” & name & “*”
field: address
criteria: like “*” & address & “*”
field: category
criteria: like “*” & category & “*”

SQL code:
SELECT customerName ,address,category
FROM prospectiveCustomers
WHERE customerName LIKE “*” & name & “*” AND address LIKE “*” & address& “*” AND category LIKE “*” & category& “*”;

That works, but only for one value in a textbox. Once there is more than one value in a textbox (e.g name: bob,smith), the query returns no records.

I have also tried splitting the values using the comma as a delimmter, then inserting the values into a new table. That is fine until one of the search criteria textboxes has been left blank. So the query I created will run, but returns no records.

SQL CODE:
SELECT prospectiveCustomers.name, prospectiveCustomers.address,prospectiveCustomers. category
FROM prospectiveCustomers, [SearchCriteria-name], [SearchCriteria-address],[SearchCriteria-category]
WHERE prospectiveCustomers.name Like [SearchCriteria-name].name AND prospectiveCustomers.address LIKE [SearchCriteria-address].address AND prospectiveCustomers.category LIKE [SearchCriteria-address].category;