My Temp gauge is rising and dropping

[Willturtle]

I replaced my Heater Core on my 2019 Ram 1500 Tradesman, last month. I still have condensation dripping on my passenger floor board. I also now have my Temp gage rising the dropping when I turn the A/C on.. What should I be checking for, I had a Diagnostics ran on it and it just reads the shutter grille not working. I believe the shutter grille has been out for 2yrs now..

 

[HSKR R/T]

I replaced my Heater Core on my 2019 Ram 1500 Tradesman, last month. I still have condensation dripping on my passenger floor board. I also now have my Temp gage rising the dropping when I turn the A/C on.. What should I be checking for, I had a Diagnostics ran on it and it just reads the shutter grille not working. I believe the shutter grille has been out for 2yrs now..

How much is your coolant temp fluctuating? did you get all the air out of the system after replacing heater core? Did you clean the drain line for the condensate? If you have condensation dripping, that has nothing to do with the heater core.

It's possible if your blend door isn't working properly you A/C may be cooking your hester core causing temp fluctuations