Alright. I had to put a pigtail on my S-10, but there was a standard off the shelf plug in available for it from any autoparts store.
The '02 Avalanche came with a trailer connector below the bumper. Just plug in and go.
My '03 Silverado came with a trailer connector below the bumper. Just plug in and go.
Even the wussy little '04 Colorado atleast had a standard 4 pin trailer connector. Just plug in and go.
The brand new 2008 4wd Silverado with heavy towing package that I bought specifically (the 4wd part) for launching my boat on dirt ramps comes with a fake piece of plastic in the back bumper. If you read the owners manual it says you can buy a special adaptor from GM to connect to your trailer. Sure sounds like U-Haul to me.
Its late, I'm tired. It took me about 30 minutes to cut off their stupid plug to plug into their special adaptor and hook up a regular large seven pin receptacle and mount it in the bumper, but still. I was already hooking up the boat when I realized I couldn't. How irritating.
It had to cost more for them to make their special connector so they could sell their special adaptor than just buying an off the shelf receptacle and bybassing the whole annoying process.