My car warms up very slowly and never gets hot inside like it used to. Both of the ac/heat cluster lights are out and the temperature gauge always leans towards the cold side. Also, after a quick scan concerning my check engine light, the code had something to do with a thermostat.
My heat doesn't get as hot as it used to. on 2005 Buick Century
The thermostat may be stuck open not allowing the cooling system to get hot as it should. I would say you have a stuck open thermostate. It's a cheap fix about $30 in aftermarket parts. You will need the thermostat, thermostat gasket and a gallon of coolant 50/50 mix dexcool.