Custom referencing module searching in Sitefinity 7.2

I am having problems in custom module search.
In my case I have a custom module “brand” with fields shown in Image. (See brandModule.png)

In this module there are two fields (Category, Subcategories) which are causing problem because when I delete those fields everything started working fine.

These two fields actually referencing another module (both fields reference the same module) which is “Category” with fields as shown in the image. (See CategoryModule.png)

In this module there is a field ParentCategory which is referencing the same module(it self).
Now I have created a searchIndex as shown in the image. (See MySearchIndex.png)

I have selected the “brand” module to and set its default page where the brands are published.

After that when I try to search any of these brand items I don't find any.  

After spending a lots of time, finally I found the actual problem, The actual problem was with the field Name ("Category") in the "brand" module because I think this field name is already reserved for module's default field names, this is why search index not indexing the brand modules items.
Hope this may help others as well.