ok i installed an overhead console in my 98 astro van with compass and temp gauge, well a friend of mine wanted one too so we went and got him an overhead and we installed it useing the factory harness, his overhead has compass temp and mode.. mode tells you mileage average fuel used, etc. when we first plugged it in i it gave us all kinds of information on the mode selection...thats great!!! But after about 2 minues, it zeros out, almost like it resets itself. the only thing that works after that is the compass. Everything on the display still lights it just shows zeros, or lines. Am i missing something for this overhead that i did not grab? Maybe a control module?? Also his van is a 96 safari and mine is a 98 astro, and we tried it in both vans and got the same results. any thoughts?