Occasionally the radio will turn off, which.

Occasionally the radio will turn off, which also affects the windows and wipers. It usually happens in dry weather, in fact it has never happened in wet weather. I see responses on the internet claiming it is a faulty body control module. How do I change that part, where is it, etc? Or. Are there any other ideas? This seems to be a common problem with 99 & 00 Escalades. Thanks for any help!