Q: Coolant temperature gauge does not move at all. 1998 Ford Ranger

Hi there - most likely the coolant temperature sensor (for the gauge, not the coolant sensor that drives the fuel injection - there are usually two) is toast. This can be checked with an ohm meter. A reading of 2K ohms when cold, or a few hundred when at operating temperature are typical - check your Ford service manual for specifics for your sensor. If the coolant temperature sensor checks out, it is the wiring or the gauge itself. I recommend an electrical component inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, confirm this diagnosis, and give you an accurate assessment of damage and cost estimate for repairs.