Most times when you have light colored stools or even gray colored stools it can be due to a blockage of the biliary ducts.
There's also several other things that could cause light colored stools such as certain medicines, Gallstones, tumors of the liver that could be noncancerous or cancerous, bile ducts that have cysts, Alcoholic Hepatitis, Sclerosing cholangitis and even Biliary cirrhosis.
Having light colored stools is not normal and you should see a doctor to be sure nothing serious is going on that could be fixed.