Expert: Roland Finston - 10/16/2011

Question
QUESTION: i have a 2000 chry lhs 3.5 both heater core line are hot but blows out luke warm air

ANSWER: I think it is the blend door. There may be a self-calibration built-in to the unit. Start the engine, turn on the control unit if it is the ATC type, then set the controls to full cold and let it run for two minutes, then set it to full hot and let it run for 5 minutes. Then see if you have regained control of the temeratures. If not let me know and I can tell you how to check out the function/removal of the blend door motor which control the air temp.
Roland


---------- FOLLOW-UP ----------

QUESTION: Thanks roland I tried it an it worked for a min then air went back to like to. Luke warm

ANSWER: Hi Chuck,
The next logical step would be to check for whether the control unit has recognized the problem and entered a fault code as to what it thinks is the problem. The procedure to do that is different for the manual control unit or the automatic control unit with digital temp readout. Let me know which type of unit you have and I will tell you the procedure to do the code readout.
Roland

---------- FOLLOW-UP ----------

QUESTION: Its digital

Answer
Hi Chuck,
The control head can only be placed into the diagnostic mode while the engine is running and the vehicle is not moving. Set the control to a 75° F setting (so there is no confusion with the 23-51 Diagnostic Trouble Codes (DTC's)

To place the system into it's diagnostic mode, press and hold the Floor, Mix and Defrost buttons (at the same time) The ATC head display will begin to blink. Release the Floor, Mix and Defrost buttons. Once the control head enters the diagnostic mode, the display on the control head will continue to blink. This occurs until it completes its tests and climate control unit door/actuator calibrations. Then it will display any diagnostic trouble codes that are present in the BCM. If there are no diagnostic trouble codes, the system will return to its normal operation as indicated by the temperature symbol (a C or a F) Diagnostic trouble codes related to the ATC and climate control unit will appear on the display in numerical form. The diagnostic trouble codes are stored in the BCM and can range between 23 and 51. The ATC control can only show one diagnostic trouble code at a time. Under certain circumstances, more than one diagnostic trouble code could be in the memory. To scroll through any additional diagnostic trouble codes, press the Panel Mode button on the ATC control. It is important that no other knob or button is pushed until all codes are read. Pushing any button except Panel Mode or turning a knob will end the diagnostic test without showing the rest of the trouble codes.
Roland