The new cruise controller has the heatsink on the bottom. It also has mounting holes so that it can be affixed to a metal plate. But there is very little transfer area and if you fix your controller to a metal plate, the plate will block the wind blowing over the bottom of the controller.
I learned this the hard way and fried my 10 month old controller.
I have emailed TOM and posted a message here in the GM staff area.
I have not heard anything back. This is typical of GM's total lack of customer service. I have been spending some time on Endless Sphere and the consensus there is that GM wheels can be made good if you can get them centered and true but that GM controllers are "a joke."
Given the total lack of customer service and the number of things that can go wrong with a complicated piece of electronics like a controller, I cannot recommend buying controllers from GM.
The first one I bought was DOA and the cruise controllers have this fatal design flaw.
