If you still are having problems, the way the sending units work is based on resistance to ground. Generally as the resistance to ground decreases the gauge reading increases. This makes testing the actual gauge relatively easy. Take the wire off the sending unit on the fuel tank or engine and short it to ground. Make sure you are getting a good connection to ground when you short it and see if the gauge reading goes up. If it does it is more than likely your sending unit. for fuel I usually find that the float has a hole in it and needs fixed or replaced. If the gauges don稚 respond to a short to ground it is usually the connections on the gauges are corroded and need cleaned up, or in the unlikely event the gauge could be bad. Check to make sure the gauges work first. If not check back in and we can go further into the gauge panel. As for the gauges that read up when they should be down (temp in red all the time). Disconnect the wire from the sending unit and it should go to cold. (make sure the wire does not short to ground if your trying to get the gauge to go down)