The thermometer needle on the dash board stays at the lowest it can...My heater also does not work. I know these two are linked some how because the other day the heater randomly began working and so did the thermometer needle(which shows how heated your truck gets next to the MPH) I flushed my radiator completely today...but that didn't do anything? Also, after i flushed the radiator i left my truck on for about 20 minutes and the new coolant i had put in the radiator was not hot?? HELP I'M RUNNING OUT OF PATIENCE...and MONEY! =D