My friend has a 97 F150 with 4.6 and the temp guage quit working, he replaced the sensor and it's not working, I checked the sensor and it's blown, I checked the line voltage and it's 11 volts a repaire manual said it should be 5 volts. Anyone know what caused the voltage increase???

 

The Temp gauge quit working on my 97 F150 also. I had to replace the instrument cluster. When the I shorted the the plug for the sensor the gauge would read hot and when I left it open it would read cold. The manuals said to replace the sensor. That didn't work at all. When I used a variable resistor to replace the sensor, the guage would either read cold or jump to hot as I change the resistance of the pot. The instrument cluster regulates the voltage used for the sensor to about 5 volts so the instrument gauges do not change reading as the voltage from the battery varies.