Heating Problem

[MENTION=87687]LTDSC[/MENTION] Are you guys calling the ambient sensor the one to the left of the steering wheel inside the cabin?
 
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maybe not quite the same problem

Had to register to hop on this thread, and I know there are some similar ones about cabin heating abnormalities... 2004 V6 4Runner
I cleaned the sensor, which was crudded up, but maybe only a little effective. Also cleaned the cabin air filter just prior, just because, and it was filthy, but didn't change the symptom: the heater doesn't seem to be able to keep up with the fan.
What I mean is, if you crank the heat and have the blower on low or 1, it heats up and blows a bit of warm air. When you are driving I notice the fan seems to blow a little faster. But when you crank the fan to 3 or Hi, you get warm air for a few seconds and then cold air. It's cold outside, in the 20s and 30s, but if I select recirculating air I get the same result.
I have removed and re-inserted the relay in the fuse box but don't know if a heater that works at all would be something a defective relay or a fuse would involve. Any thoughts appreciated.
 
jhwitul said:
Had to register to hop on this thread, and I know there are some similar ones about cabin heating abnormalities... 2004 V6 4Runner
I cleaned the sensor, which was crudded up, but maybe only a little effective. Also cleaned the cabin air filter just prior, just because, and it was filthy, but didn't change the symptom: the heater doesn't seem to be able to keep up with the fan.
What I mean is, if you crank the heat and have the blower on low or 1, it heats up and blows a bit of warm air. When you are driving I notice the fan seems to blow a little faster. But when you crank the fan to 3 or Hi, you get warm air for a few seconds and then cold air. It's cold outside, in the 20s and 30s, but if I select recirculating air I get the same result.
I have removed and re-inserted the relay in the fuse box but don't know if a heater that works at all would be something a defective relay or a fuse would involve. Any thoughts appreciated.
Click to expand...
Heat comes from engine coolant circulating through the heater core. Only the blower is electric.

The fan going faster while driving seems to be normal, and I don't think it's related to your problem.

One possibility is that your thermostat is stuck open, so the radiator is cooling off the engine faster than it can warm up, and you get cold coolant through the heater core. Normally when the engine is cold the coolant only goes though the heater core until it's hot enough to open the thermostat and go through the radiator too.

Another possibility, since you mention things having filthy crud, is the air side of the heater core could be dirty. That could be more likely if you smoke, have pets, or live in a very dusty place.

Another less likely possibility is that the internal coolant passages in the heater core could be plugged. I don't think that's common.

Another possibility is that the air temperature baffle is not staying in the right place. Or you have the defrost on so the A/C is running cooling it off more than the heat can keep up. (the A/C light doesn't go on, but you can hear the compressor kick in). You can pull the A/C Mag Clutch relay to disable it, but you will cause an error in the climate control system (stupid computerized climate control).

If you keep driving, does it warm up eventually? Do you have the problem when set to something other than defrost?
 
I am new to the 4runner world. I just purchased a 2004 4x4 sport edition with 4.0 v6. Motor warms up fine (scan tool shows 190 ish degrees), blower and all controls seem to be working fine, but I get good heat heat from Drivers side vent closest to the window, and then it gets colder with each vent progressing towards the passenger window. At Idle, I get no heat on the passenger side but if I run engine at 2500 rpm, I can get SOME. I took it to a mechanic that seems to thing that there is something wrong with the blend door for the climate control.. I am not convinced.

Could I have an issue that a good back flush will fix?

I just don't know that much about the system yet to have an educated discussion with mechanic.
 
chefbill65 said:
I am new to the 4runner world. I just purchased a 2004 4x4 sport edition with 4.0 v6. Motor warms up fine (scan tool shows 190 ish degrees), blower and all controls seem to be working fine, but I get good heat heat from Drivers side vent closest to the window, and then it gets colder with each vent progressing towards the passenger window. At Idle, I get no heat on the passenger side but if I run engine at 2500 rpm, I can get SOME. I took it to a mechanic that seems to thing that there is something wrong with the blend door for the climate control.. I am not convinced.

Could I have an issue that a good back flush will fix?

I just don't know that much about the system yet to have an educated discussion with mechanic.
Click to expand...

I have a 2004 Limited and I have Dual Climate Control, I can set the temperture differently for driver and passenger sides, I'm assuming that you don't, if you don't then I would say your mechanic is correct or you have a partially blocked heater core.

I did a search of the forum for your problem, here's the link to the search results, one or more of the topics make have a solution for your issue.

http://www.toyota-4runner.org/gsear...hp?do=showpm&pmid=841305&ss=13257j23503745j26
 
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I have an 2007 and similar problems. Sometimes it will heat fine and sometimes it will heat up once and then blow semi cold air. I have to drop the set temp to get it to blow warm again. I will check my cabin sensor and see if that will fix it.
 
ScottD said:
I have an 2007 and similar problems. Sometimes it will heat fine and sometimes it will heat up once and then blow semi cold air. I have to drop the set temp to get it to blow warm again. I will check my cabin sensor and see if that will fix it.
Click to expand...

The climate control is designed to only blow warm or cold air depending on the temperture setting, if you have it set at 70* it will blow cold air if the temperture is more than 70* in the vehicle, if lower then the setting it will blow warm air, if your interior is not up to the temperture setting and it's still blowing cold air you most likely are having sensor issues.
 
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Yes, but when it is 20F outside and I set it on 68 it will blow warm for a bit and then blow cold - or what feels like cold. It may be just neutral air blowing that feels cold but either way I end up having to cut it off or change the temp to get it to stop.

I saw the cleaning of the temp sensor thing and thought maybe mine is dirty and keeping the temperature from sensing as fast as it should.
 
If you have a decent wall thermometer, etc. that you can use, you can check the interior temperture to compare it to the settings.
 
Same problem

2005 4runner with same problems. I did the thermostat and flush with no help. I'm almost positive it has something to do with the blend door. Anybody have an update?

Thanks
 
LTDSC said:
Figured it out today. My ambient sensor wasn't as clean as I thought. Used some sensor cleaner and a rag. Cleaned the tube and the sensor along with the casing of it. Helped instantly.
dbff2f1bf031d47fe06d19a2736663d3.jpg

Little dirty
Click to expand...

LTDSC, This is good to know. I am going to give this a go. So the Ambient Temp Sensor is the one behind the little grill below the ignition? Thax
 
So I have a 2005 SR5 without dual climate control, and I am having a similar problem. Kind of...

When I turn the heat on I get warm air on the drivers side all the time and on the passengers side for a few minutes then it blows barely any warm air.

Why would I be getting warm air on one side and not the other. Is there a blend door for each side?
 
Hey guys, new to the forum, I'm having a very frustrating issue with my 2003 4runner SR5.

Just bought it and only noticed the issue this morning.

Air is warm when accelerating but cools down very quickly as the engine winds down. Almost cold coming out when I'm sitting at a light.

I've read so many posts that say so many things(heading core flush, water pump, low coolant, aftermarket stereo), I just don't know where to start.

I've got coolant full in the reservoir, first thing I checked.

In one post I read something about the radiator hoses being different temps.

My in and out tubes in the radiator are not the same temp. One hot one not.

I am not a car genius, any help would be appreciated.
 
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