Heater blowing cool air

Tiny
CHRISBRADBERRY
  • MEMBER
  • 2002 TOYOTA CAMRY
Four cylinder front wheel drive automatic 170,000 miles.

XLE model with automatic climate control. Heater coil is getting hot, but air from vents is staying cool. Air is apparently not being circulated over the heater coil for some reason. All other climate control functions appear to be working fine. The problem would seem to either be a bad climate control module or else something broken or jammed in the system which is preventing the air from circulating through the heater coil. I am getting a little bit of warm air on the driver's side, most of which comes through the driver's side upper vent when the air is being directed through the upper vents. Air from all other vents is cool.
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Monday, December 14th, 2009 AT 11:02 PM

9 Replies

Tiny
BMRFIXIT
  • EXPERT
Since heater core is hot suspect and check blend door operation.
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Tuesday, December 15th, 2009 AT 7:56 PM
Tiny
CHRISBRADBERRY
  • MEMBER
Yes, that is what I would think to check next, but how do I check it? Where is the blend door located? How do I access it to check it? And is it something that can be repaired without replacing the whole system? Thanks.
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Tuesday, December 15th, 2009 AT 8:47 PM
Tiny
BMRFIXIT
  • EXPERT
Air mix control motor is located behind right side of dash. Switch between hot and cold and check if moving the door.
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Tuesday, December 15th, 2009 AT 10:13 PM
Tiny
CHRISBRADBERRY
  • MEMBER
I found the air mix control motor, and it seems to be moving fine; up and down when the temp setting is changed.

I have concluded that warm air is blowing on the drivers side but cold air is blowing on the passengers side. When air is blowing through the floor ducts the drivers side duct blows warm air and the passengers side blows cold air. When air is blowing through the vents in the dash the drivers side vent on the far left side of the dash blows the warmest, the next vent over (just to the right of the steering wheel) blows a little cooler, the next vent over blows even cooler, and the far right passengers side vent blows the coldest. The car does not have dual climate control, but it is kind of acting like it does.

I had already flushed the heater core from the outside before I got to looking at the air mix control motor, and it seemed to flush fine. Is it possible for one side of the heater core to be clogged such that only the drivers side of the core has coolant flowing through it? Could the water pump not be pumping hard enough to fully circulate the coolant and consequently only part of the heater core is getting hot?

I also had already removed the thermostat and put it in boiling water to make sure it was working, and it was. Also, the engine temperature gauge is steady, so I do not think there is any problem with circulation of the engine coolant.

Does the air mix control door inside the heater assembly have two pieces such that the piece on the drivers side could be moving whereas the piece on the passengers side isn't?

I am perplexed. Any other ideas? Thanks.
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Friday, December 18th, 2009 AT 9:34 PM
Tiny
BMRFIXIT
  • EXPERT
Let try and get some codes from it, and let me know what you have for codes.

Turn the ignition switch on while pressing the A/C control auto switch and right front switch simultaneously.
Check that the indicators light up and go off at second intervals four times in succession.
After the indicator check is completed, the system enters the DTC begins automatically.
Press the off switch when desiring to cancel the check mode.
DTC check (sensor check)
Perform an indicator check. After the indicator check is completed, the system enters the DTC check mode automatically.
Read the code displayed on the panel.
.
If the slower display is desired, press the front defrost switch and change it to stepped operation. Each time the front defrost switch is pressed, the display changes by 1 step.
.
Clearing DTC:
To clear diagnostic trouble code, there are two ways.
During sensor check, press the "defrost switch" switch and "rear switch" switch at the same time.
Pull the ECU-B fuse in engine room J/B for twenty seconds or longer to clear the DTC memory.

Actuator check:
After entering the DTC check mode (sensor check mode) press the right frong switch.
Since each damper, motor and relay automatically operates at 1 sec. intervals beginning in order from ten in the temperature display, check the temperature and air flow visually and by hand.

If the slower display is desired, press the defrost switch and change it to step operation. Each time the defrost switch is pressed, the display


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Saturday, December 19th, 2009 AT 4:50 AM
Tiny
CHRISBRADBERRY
  • MEMBER
It flashes 21, and beside the 21 the symbols for upper vent, fresh air, and fan are also flashing on the screen. When I clear the code it goes to 00 and then immediately flashes back to 21.
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Saturday, December 19th, 2009 AT 11:04 AM
Tiny
BMRFIXIT
  • EXPERT
DTC 21: SOLAR SENSOR CIRCUIT
Circuit Description
A photo diode in the solar sensor detects solar radiation and sends signals to the A/C amplifier.

Remove A/C amplifier with connectors still connected.
Turn ignition switch ON.
Measure voltage between terminals S5 and TS of A/C amplifier connector when the solar sensor is subject to an electric light, and when the sensor is covered by a cloth
Voltage:
Sensor subject to electric light: 0.8 - 3.3 V
Sensor is covered by a cloth: Below 0.8 V
HINT:
As the inspection light is moved away from the sensor, the voltage increases.

A: GO TO NEXT STEP.
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOM TABLE
C: CHECK AND REPLACE HEATER CONTROL HOUSING SUB-ASSEMBLY
INSPECT COOLER (SOLAR SENSOR) THERMISTOR
Remove cooler (solar sensor) thermistor.
Cover sensor with a cloth.
Measure resistance between terminals 1 and 2 of solar sensor connector
Resistance: infinity ohm (No continuity)
HINT:
Connect the positive (+) lead to ohmmeter to terminal 1 and negative (-) lead to terminal 2 of the solar sensor.
Remove the cloth from the cooler (solar sensor) thermistor and subject the sensor to electric light
Measure resistance between terminals 1 and 2 of solar sensor.
Resistance: Approx. 10 kohm (Continuity)
HINT:
Connect the positive (+) lead to ohmmeter to terminal 1 and negative (-) lead to terminal 2 of the solar sensor.
NG: REPLACE COOLER (SOLAR SENSOR) THERMISTOR
OK: GO TO NEXT STEP.
CHECK HARNESS AND CONNECTOR (BETWEEN COOLER (SOLAR SENSOR) THERMISTOR AND HEATER CONTROL HOUSING SUB-ASSEMBLY)
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: GO TO NEXT STEP.
CHECK AND REPLACE HEATER CONTROL HOUSING SUB-ASSEMBLY


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Saturday, December 19th, 2009 AT 7:42 PM
Tiny
CHRISBRADBERRY
  • MEMBER
The heater core must have been clogged on the passengers side. I removed the core and flushed it several times back and forth and then reinstalled it. I am now getting warm air on both sides of the cabin, not just on the drivers side as I was before. Thanks for your help.
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Saturday, December 19th, 2009 AT 9:07 PM
Tiny
BMRFIXIT
  • EXPERT
Thank you for your donation and using 2carpros. Com and for updating the final fix.
Enjoy and drive safe.

Thank you,
Jack O
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Sunday, December 20th, 2009 AT 11:29 AM

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