My 1990 Mx-6 GT gages are not working. I took out the instument panel & put in another one. When I go to turn on the car on the temp gage goes right to the middle and my gas gage doen't go up or down. I'm thinking it's a ground cable.I just don't know which one to check.Can anyone help me? Also when I changed the instument panel I didn't disconect the battery. Should I disconect and reconect the battery to see if the gages work?