QuestionI have a 1998 Chrysler Concorde with a 2.7L engine that I am having a heat problem with. I cannot get warm air to blow in the car unless I am driving it at speeds of 30 MPH and above. In the winter when I "warm" the car before I drive it, it doesn't do anything other then freeze my windshield more because it only blows freezing cold air until I drive it. Even after the temperature of the car is warm, I still only get warm air to blow when I'm driving. As soon as I stop at a light, it immediately starts to blow cold air only. Also blower will not work unless it is on high.
AnswerHi Evalyn,
First, I assume that you have the conventional heater/ac control panel with knobs and buttons but no illuminated digital readout (called the automatic temp control), correct?
If that is the case, then it sounds like you either have too low a temperature in the coolant water circulating through the system or you have an impediment to the flow of that coolant through the heater core in the cabin. What is the temp gauge showing on the instrument cluster when you are warmed up? It should ideally be in the range of 1/4 to 3/4 of full scale. If it is always just at 1/4 or less then your thermostat may be stuck open.
As to the other issue of flow impediment tha way to check for that is open the hood, after you have been driving for a while to warm up the system, and locate two medium diameter rubber hoses at the firewall between the engine and the cabin, about in the middle of the panel, and touch both of those hoses to see whether one is noticeably hotter than the other. Were that the case then that would suggest the core is partially blocked. That can be corrected by reverse flushing the heater core to drive out deposits that are blocking the flow. A radiator shop can try that fix at a modest cost. If the hoses feel about equally HOT, then the flow is good and we have another fix to try if that were the case. Let me know.
On the blower motor, that is due to a part called the 'blower motor resistor block' having failed. That is easy to replace being located under the dash on the passenger side, mounted in the underside of the heater/ac unit, just to the left of the round lid that covers the blower motor proper. Locate the motor by turning it on and listen/feel on the housing. You will see a pair of wires between the blower motor and the resistor block. Just remove the plug at the block (about 5 wires in the plug) remove the screws next to the plug socket and the block will drop down and out for replacement. There is on the lower edge of the dash a small silencer panel/duct that if removed will give you a better view. It is held in place by a fastener at the end and pivots off a connector at the other end, I believe.
The defrost running cold air is correct, as cold dry air is what helps clear the condensation.
Let me know if I haven't understood the situation or anything I suggested doesn't solve it.
Roland
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