Heating Problem

[Jordankeen]

I have a 2004 toyota 4runner SR5 and I'm having problems with my heating and front windshield defroster. When I start my car and it is idling air does come out of my vents but if i set the temperature to 75 degrees once the car warms up it still blows cold air. Only when I put it in drive and actually start driving my car is when the heat becomes warm. This goes the same way for my front windshield defroster. Any thoughts?

 

[audiqtr]

I guess I have somewhat of a parallel issue. My heater doesn't really blow hot unless the temp is set to at least 80. Being in California, I rarely use the heater and I noticed that this last weekend.

Free bump for you my friend...

 

[RickC]

Sounds like the thermostat is stuck open.

 

[berglar]

I have an '07 that I got about a month ago with 1 month of warranty left so I have been trying to notice anything wrong. I do not have the heater on "Auto" and the temp is set to 74. When it is cold outside the heater puts out hot air but when it is warm outside, it puts out cooler air. My guess is that the temperature setting is like a house furnace with the fan always running. The heat comes on and off as needed to keep the temp at the setting but the fan keeps blowing. Does anyone agree or do I have a problem.

 

[DaveS]

I had a similar experience early on with my 04 after a block heater was installed - do you have one? Turned out the block heater itself was bad and somehow that was causing the issue - don't ask me how - but once they replaced it all was good.

 

[sr5hi]

I have a 2004 toyota 4runner SR5 and I'm having problems with my heating and front windshield defroster. When I start my car and it is idling air does come out of my vents but if i set the temperature to 75 degrees once the car warms up it still blows cold air. Only when I put it in drive and actually start driving my car is when the heat becomes warm. This goes the same way for my front windshield defroster. Any thoughts?

You may have a problem with the HVAC controls that direct vacuum to the vacuum motors that control the opening and closing of various doors that direct air flow (hot or cold) out of your dashboard vents. Or you may have a problem with one or more of the vacuum motors or hoses in the system that may be leaking vacuum. As your engine rpms increase, the amount of vacuum increases, which may be enough to operate the doors properly. If you did not have this problem before with the lack of warm air after the engine is warmed up, this may be the problem.

 

[12vman]

Any solutions?

Has anyone figured out their issue, whether it was a themostat, or vacuum hoses, or something else? How did you figure it out? Thanks!

 

[flojules]

Front Heating Issue

I just purchased an '07 that has great heat output for the dash but when I select the dash/floor combo or just floor, there is hardly any output. It actually feels like nothing is happening unless I blast it on high for a while only on the floor setting and leave it on that. Has anyone else experienced this or have any suggestions?
Thanks!

 

[wjt209]

I had a heating problem at least I thought. Temp outside was 65 and I had the heat set on 71. In town the inside did not warm up. The Toyota dealer told me that I had to set the heat inside at least 10 degrees warmer than the outside temp. I now put the inside temp 12-15 degrees warmer than the outside . I does not take liong to heat up and than I can put it at 71 and it stays there. Makes no sense to me but on my 2004 it works.

 

[gassface]

You may have a problem with the HVAC controls that direct vacuum to the vacuum motors that control the opening and closing of various doors that direct air flow (hot or cold) out of your dashboard vents. Or you may have a problem with one or more of the vacuum motors or hoses in the system that may be leaking vacuum. As your engine rpms increase, the amount of vacuum increases, which may be enough to operate the doors properly. If you did not have this problem before with the lack of warm air after the engine is warmed up, this may be the problem.

I have this issue. Is there a DIY fix?

 

[flojules]

Thanks. I will try this. It makes some sense as that I think about it. Hope it works!

 

[LTDSC]

mine just started this similar issue. It happened after the timing belt job was done.

It was at 75* temp and 63* outside, blowing cool air. I had to crank it to 80* to start to feel the warmth. Which is not how it used to be prior.

Any ideas? Im stumped because both should be unrelated.

 

[BlackWorksInc]

mine just started this similar issue. It happened after the timing belt job was done.

It was at 75* temp and 63* outside, blowing cool air. I had to crank it to 80* to start to feel the warmth. Which is not how it used to be prior.

Any ideas? Im stumped because both should be unrelated.

Did you have the belt done at a shop or did you do it yourself?
Was the thermostat replaced and if so did you use a Toyota Thermostat or aftermarket one?
Perhaps the system was not bled correctly?

Normally when we do anything with the cooling system we do the following when bleeding the system:

• Put the heater on full temperature (no Auto)
• Set the blower to the lowest setting
• Run the engine until its nice and toasty and the thermostat opens (I use an IR thermometer to see that the two hoses are about 20~30°F of each other)
• Optional- Use a stick or brake pedal depressor to set the idle around 2,000~2,500rpm for about 5minutes to make sure everything is nice and toasty
  
  The procedure above is how we normally get most if not all the air bubbles out of the system. I personally use the following tool when bleeding the system as I feel it is the most efficient manner and allows you to observe bubbles:
  
  
  
  
  
  Post Note-
  I would also check and see if the interior temperature sensor is not dirty. Its that little guy behind the slotted vent under the ignition switch dash kick panel.

 

[LTDSC]

Did you have the belt done at a shop or did you do it yourself?
Was the thermostat replaced and if so did you use a Toyota Thermostat or aftermarket one?
Perhaps the system was not bled correctly?

Normally when we do anything with the cooling system we do the following when bleeding the system:

• Put the heater on full temperature (no Auto)
• Set the blower to the lowest setting
• Run the engine until its nice and toasty and the thermostat opens (I use an IR thermometer to see that the two hoses are about 20~30°F of each other)
• Optional- Use a stick or brake pedal depressor to set the idle around 2,000~2,500rpm for about 5minutes to make sure everything is nice and toasty
  
  The procedure above is how we normally get most if not all the air bubbles out of the system. I personally use the following tool when bleeding the system as I feel it is the most efficient manner and allows you to observe bubbles:
  
  
  
  
  
  Post Note-
  I would also check and see if the interior temperature sensor is not dirty. Its that little guy behind the slotted vent under the ignition switch dash kick panel.

• 
  it was done at local Toyota dealership i worked at. They replaced the thermostat i believe. Ill clean the interior sensor as well.

 

[mid9pitstop]

Agreed!

Sounds like the thermostat is stuck open.

+1, that would be the area that I would check first.

Cheers!

 

[LTDSC]

cleaned the sensor, hasnt seem to help it just yet. 70-73 blows cool, i have to go to 76-80 to get the heat. I guess at least i still have heat.

Also noted when turning up my temp fast it throws it to floor vent when NOT on Auto. Is this normal or is my system having issues?

 

[20034RunnerV84x2]

You may have a problem with the HVAC controls that direct vacuum to the vacuum motors that control the opening and closing of various doors that direct air flow (hot or cold) out of your dashboard vents. Or you may have a problem with one or more of the vacuum motors or hoses in the system that may be leaking vacuum. As your engine rpms increase, the amount of vacuum increases, which may be enough to operate the doors properly. If you did not have this problem before with the lack of warm air after the engine is warmed up, this may be the problem.

They aren't run off of vacuum on 4th gens. It's electronic.

 

[20034RunnerV84x2]

cleaned the sensor, hasnt seem to help it just yet. 70-73 blows cool, i have to go to 76-80 to get the heat. I guess at least i still have heat.

Also noted when turning up my temp fast it throws it to floor vent when NOT on Auto. Is this normal or is my system having issues?

That's normal. It'll do it for other ways too, turn on defrost and it turns on fresh air (or something like that).

 

[LTDSC]

still having issues. I cleaned the sensor inside and unplugged/replugged the control unit inside. I had to crank it to 80* to get light heat out. Meanwhile my engine temp gauge is at 1/4-just below half way. Its 65* out and used to be middle of the gauge on the highway. I wonder if my thermostat is stuck open.

 

[LTDSC]

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.

Little dirty