Mechanics

HEATER WONT WORK

2001 Mercury Mountaineer • V8 2WD Automatic • 121,091 miles

The air conditioner works all switches work, the the heater will not come on.
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Muttnru
December 23, 2010.



Do you mean the temp of the air is not hot enough or that the blower is not working?

Wrenchtech
Dec 23, 2010.
Blower works but it will not get hot. Thermastate is good. All valves are working to heater core. It will not change from air to heat.

Tiny
Muttnru
Dec 23, 2010.
With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both too hot to hold. If they are.

The heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

Wrenchtech
Dec 23, 2010.