1999 Pontiac Grand Prix temperature gauge doing strange things

[bdog57]

1999 Pontiac Grand Prix GT.
I have replaced the, radiator and the cap, the temperature sender and the coolant, Now, the temperature gauge goes all the way to hot when I first start the vehicle and stays there even after I turn the key off. In order to get the gauge to go back down, I have to turn the key on and off several time, it goes down a little each time.:th_scratchhead:

 

[Fivefingerdeathpunch]

Sounds like either a wire issue to the ECT sensor or the new sensor is faulty.

 

[ILoveAudi]

Temp gauge problems happen all the time. Wiring or sensor most likely. Just like Five said

 

[BillBoost37]

Try unplugging the ECT and turning the key to on (not start), does the gauge drop to zero?

 

[Frosty]

ALOT of part store temp sensors read max temperature in our cars for some reason. Do what bill said and unhook it and see if it goes full cold.