I had air trapped in my heater core, so I flushed out the heater core earlier this morning hook everything back up and purged the cooling system filled it to the top. This took care of my gurgling air trapped issue. I then installed the new radiator cap and took the car for a ride everything worked fine. I then proceeded to the auto store to buy a new battery as my battery is on borrowed time and I replaced the battery along with my air filter. I got in the car started it and drove away and my temperature sensor dropped to the lowest temperature setting, essentially not working. If I turn the car off and let it sit off and then turn it back on it will work for a moment or two and then drop back to the lowest setting. Could this be something to do with installing the new battery and playing with the cooling system at the same time, I am not quite sure what it could be keep in mind that it's raining where I am and I got a lot of water and fluid in the engine could it be a short out due to moisture? I didn't touch the thermostat or any of the other sensors so the only contact I had with the electrical system today was replacing my battery please help.