Park Assist on Silverado 2008

My park assist on my Silverado truck worked for 1 year with the hitch inserted. Now I cannot turn on park assist with hitch in. I am told by GM that the park assist doesn’t work with a hitch. Nothing changed by me during that year. How do I get the park assist to work when I am trying to connect my trailer?

There Are GM TSBs (Technical Service Bulletins) Advising Technicians On Park Assist Problems.

The way I see it they say that a large number of mirrors are being replaced under warranty when there is nothing wrong with them. Gm says the problems are more likely in wiring or respective door modules and to check those items first.

CSA