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Heater blowing cold air

Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
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, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
CHRISBRADBERRY
  • MEMBER
  • 5 POSTS
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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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
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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https://www.2carpros.com/forum/automotive_pictures/99387_Graphic2_295.jpg

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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
CHRISBRADBERRY
  • MEMBER
  • 5 POSTS
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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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
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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https://www.2carpros.com/forum/automotive_pictures/99387_Graphic4_59.jpg



https://www.2carpros.com/forum/automotive_pictures/99387_Graphic5_36.jpg

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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
CHRISBRADBERRY
  • MEMBER
  • 5 POSTS
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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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
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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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
JOE JEFFERS
  • MEMBER
  • 5 POSTS
  • 2002 TOYOTA CAMRY
  • 200,000 MILES
I've replaced the thermostat and water pump car ran great for four days. Then the car went to red and had cold air blowing through the vents. Eventually things went back to normal. At a stop sign the car seemed to get hot again.
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Have you checked the heater core for a restriction?ALso does your cooling fan work when its running hot?Are both the upper and lower radiator hose getting too hot to touch?
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
JOE JEFFERS
  • MEMBER
  • 5 POSTS
Both fans work. Not sure about the hoses. I just replaced the ECT sensor. Hopefully this will take care of the problem. Why would it run perfect for four days driving it 40 miles plus a day than all of a sudden it goes straight to the red line with cold air blowing through the heater? Sounded like a sensor to me? I'll see what happens. This car has 2 hundred thousand plus miles on it.
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
The running hot the ect would make sense but not the cold heater. If its running hot the heater should be hot unless you loss flow thru the heater core or had a blend door issue.
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
JOE JEFFERS
  • MEMBER
  • 5 POSTS
I'm about to flush the system. Does the blend door something that needs to be flushed? Or is an electrical item?
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
JOE JEFFERS
  • MEMBER
  • 5 POSTS
I'm about to flush the system. Does the blend door need to be flushed or is this a mechanical door?
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
The blend door is inside the car and and no coolantflows thru it. It just directs the air across the heater core or the evaporator core.
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
JOE JEFFERS
  • MEMBER
  • 5 POSTS
So far so good. Every thing working fine on the flush. One of the problems is I have a leak (coolant) at the back of the motor. I can't figure out how to take off the heat shield off the intake manifold. This is where the leak is coming from. Someone told me that there is some small water lines? Is this true? Thanks for all your help.
So far: replaced the termastate and water pump and ect and have done a complete flush. Still trying to figure out the leak.
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Not sure of the small hoses but would say those would be a heater hose or return hose. Toyotas arent my speciality saturns are. As far as that heat shield there should be bolts holding that on.
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Tuesday, March 16th, 2021 AT 6:57 PM (Merged)

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