the "Check Gauge" light goes on quite frequently when driving my Ford Ranger 95 SC STX 4.0 because of the Temperature gauge, when the air conditioning is on. The temperature here is over 35C and the light only lights on when slowing down on the highway. The pointer got only to two thirds of the ranger and never got close to the red H, but is it normal to the light to keep getting on?
Your vehicle has a thermostatic fan clutch. This is a disc with fins mounted between the fan pulley and the fan blades. When the air coming through the radiator is not very hot, the clutch does not engage, so the fan blade spins only weakly. When the radiator is hot and requires more cooling, especially when the vehicle is not moving, the thermostatic clutch engages the pulley hub to the fan hub so the fan blades spin with greater force to move more air and provide more cooling.
If the thermostatic clutch is worn or defective, the engine can overheat when the vehicle is moving at low speed or when it is stopped. This is due to lack of sufficient cooling air flow.
With the engine cold and not running, spin the radiator fan by hand. If it spins freely and makes many turns before it stops, the fan clutch should be replaced.
With the engine hot and on the verge of overheating, turn off the engine and again spin the radiator fan. You should feel resistance and it should stop quickly when you spin it. If it spins freely and goes around many times, the fan clutch should be replaced.
For professional use only: I have seen a mechanic test a thermostatic fan clutch on a hot, running engine by taking a rolled-up newspaper and inserting it into the spinning fan blade from the side. With a bad clutch, the blade stopped easily and the mechanic was able to spin the blade backwards with the engine still running, proving that the thermostatic clutch was bad. This is scary and dangerous, so I'm not suggesting that you do this, but if you have a mechanic to do repairs like this, you might mention this test as proof of a bad thermostatic clutch.