"This is why the clusters are internally diff on the 05-06 compared to 03-05. Everything working as it should BUT the battery light on due to that internal circuit missing on my 03-04 cluster that the truck expects to be there since my rig is an 05. I'm just going to have my stock cluster rebuild and sell this one."
Digital Dash Solutions, unless they increased their price, allows you to pic all kinds of customization of the dials, needles and lights and I now also have the trans temp gauge on mine. The cost was $250, shipped for free and if I sent my old cluster back, pre paid shipping, I received a lifetime warranty. I sent my old cluster to them. It was easy and plug and play when installed with no problems. The pigtail is already there, behind your cluster, for the trans temp gauge.