There could be 4 causes for your problem. I'll list them in order of most probable.
1-Thermostat for climate control malfunction.
2-Blend door for heat/ac not going completely to heat position.
3-Partcially plugged heater core.
4-Engine thermostat defective or not a hot enough stat. Even though the stat is only a year old, it could still be too cold a stat or defective. I would check this first. I could be a cheap fix.
Tuesday, December 16th, 2008 AT 3:58 PM