My heater was hardly heating at all. I replaced thermastat. A little more heat, on 1993 Mercury Grand Marquis

but not much. Blower works fine. one hose gets hot, other one cold.

by in Clinton, IN on January 02, 2013
2 answers
ANSWER by , January 02, 2013
CK FOR AIR IN SYSTEM ALSO CK HEATER CONTROL VALVE OPERATION
ANSWER by , January 02, 2013
maybe your heater core is clogged