if you have the 1500 based on the GM900 platform, then there's a fuse in the engine compartment, that needs to be activated for the controller to work.
this happened on my 2007 Avalanche when i hooked up my Prodigy BC. nothing happened until the RV shop found out about this inactive fuse.
even the local Chevy dealership service dept. were unaware of it.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC