Either the thermostat is bad or your electric fans are running all the time.
Rick
I'm a retired ASE Master/L-1 Technician. I still keep current with the latest automotive technology. Visit my blog for cool articles and TSB's: http://free-auto-repair-advice.blogspot.com
Be sure to check the coolant level before you start buying parts.
On will turn the fan or blower on continuously and auto setting will kick off and on according to the temperature setting on the thermostat.
70
If you are asking about the engine thermostat, they are not adjustable. You buy them by the temperature setting.
Each has a different temperature setting, so each needs its own thermostat.
Fever
Cycles it on and off based on attached thermometer setting
A temperature setting on a thermostat
yes
It depends on the ambient temperature and the setting of the thermostat.
Em ht stands for emergecy heat.
Depending on your temperature setting, usually the best is about 70 degrees, it's best to set the thermostat, and leave it at a constant setting. Resetting your thermostat to higher temperatures requires the furnace work harder, and will usually increase your utility bill.
The temperature at which you are comfortable. If your question involves money-saving, then contact your local power company to determine the best setting.