[elhigh]

A Scangauge II should hook right up to your Yukon. It just plugs into the OBD port. An even cheaper option is a Bluetooth adapter for the OBD port and t h e Torque app on your phone. They each have their quirks and limitations. I've used Torque with some success. For instance, it gives me coolant temperature that is otherwise not provided at all in a Prius, and only vaguely indicated in a HCH1. That's nice to have when you're experimenting with grille blocks. Of course where you are at this time of year overheating is probably close to impossible without shooting the rad full of holes, but when the weather warms you may be able to extend the grille block's season, or even leave it in place - or most of it - permanently.