what is it that tells the car to turn the heat on or keep it cool ?
#1
Racer
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HI i was wondering what is the name of the part that tells the cal weather to turn the heat on or keep it cool.
my cars parked now but i am getting some things ready and saving up money for some parts so that once i do start driving it again after they get the airbag recal done i could make sure its all good.
However i remember a few times when it gets really cold that sometime i have to turn the car off and on once or twice to get the heat to turn on.
like i could be on the road driving for like 10 or 15 minutes and i still don't have heat but if i stop the car turn it off and then start the car again then the heat comes on.
has anyone ever had this issue ?
my cars parked now but i am getting some things ready and saving up money for some parts so that once i do start driving it again after they get the airbag recal done i could make sure its all good.
However i remember a few times when it gets really cold that sometime i have to turn the car off and on once or twice to get the heat to turn on.
like i could be on the road driving for like 10 or 15 minutes and i still don't have heat but if i stop the car turn it off and then start the car again then the heat comes on.
has anyone ever had this issue ?
#3
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thank you
would it be possible that the blend door might be responsible for this ?
#5
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I checked the Coolant level today i started the car and let it run for about 15 to 20 minutes at idle the temp guage looked as if it was up to temp
i check the coolant level and it was showing just a little below the full mark on the coolant tank level
however it was still nice and cool coming out of the vents no heat i turned it off and back on several times i adjust the fan and temp and no give there either.
I didn't check it turning the temp from cold to warm i just turned it off and turn it back on i also hit the offswitch on the temp unit and than turned it back on not using the auto settings i used the manual settings whyll doing this it was 28 oF was the temp outside whyll doing this but still shouldn't there have been heat if the car was on for 20 minutes idling ?
i check the coolant level and it was showing just a little below the full mark on the coolant tank level
however it was still nice and cool coming out of the vents no heat i turned it off and back on several times i adjust the fan and temp and no give there either.
I didn't check it turning the temp from cold to warm i just turned it off and turn it back on i also hit the offswitch on the temp unit and than turned it back on not using the auto settings i used the manual settings whyll doing this it was 28 oF was the temp outside whyll doing this but still shouldn't there have been heat if the car was on for 20 minutes idling ?
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#8
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Yes exactly i can have the temp set to hi or 80 or whatever inbetween no hot air i let it sit runing for 20 to 25 minutes and no hot air
i check the coolant level as advised and i see its fin it is just under the Full mark not far below maybe like a 1/2 inch bewlow the full mark is where the level is showing it to be at
#9
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Yes exactly i can have the temp set to hi or 80 or whatever inbetween no hot air i let it sit runing for 20 to 25 minutes and no hot air
i check the coolant level as advised and i see its fin it is just under the Full mark not far below maybe like a 1/2 inch bewlow the full mark is where the level is showing it to be at
i check the coolant level as advised and i see its fin it is just under the Full mark not far below maybe like a 1/2 inch bewlow the full mark is where the level is showing it to be at
Check the fuses. Maybe the heater valve doesn't work.
#10
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Firstly, when the engine is running coolant is ALWAYS circulating (or should be) through the heater core. There is no heater coolant control valve like in the old days. You should be getting heat long before the 15 to 20 minutes as you've stated. On a cold start the coolant should be basically circulating through the engine and heater core only (the cooling system thermostat has not yet started to open) and should supply some heat (if selected) after a very few minutes. Once the thermostat starts to open/opens warm/hot coolant will also be circulating through the radiator.
You should verify that the thermostat has not failed in the open/near open position which will cause a very long warm up and/or cooler than normal coolant temps, and a lack of heat issue like you have. Modern vehicle ECMs do monitor the "time to get up to operating temp" (or similar term) and if this time is not within limits the ECM will set a code but I don't know if the ECM turns on the the Engine Check Light as well. After a cold start and after five minutes or so you should feel the top radiator hose (the engine return to rad hose) get warm/warmer/really warm with time, and the lower rad hose (the rad to engine hose) should also feel somewhat warmer which indicates that the thermostat is opening/opened. If the upper rad hose doesn't really ever get to the fairly warm stage in about ten minutes and the lower hose seems to stay pretty much cold then the thermostat may be stuck open. Has the coolant temp gauge been reaching about the mid-scale range?
You still need to verify that the temperature mixer door servo/motor is operating when the temperature selection is changed (in other words, verify that the mixer door is not stuck in the cool/cold position). After a cold start and with the system in "Auto Mode" the fan should not operate for two or three minutes (so as not to push cold air into the car) but after that the coolant should have warmed up to a programmed temperature and the fan should run. In "Manual Mode" the fan will not have the delay in operation.
Your photo of the coolant in the expansion tank looks low to me but maybe it's just the angle or my perception but it does look low compared to my car which is about an inch below the "F" mark as well. If you don't find anything conclusive with the items above, and because your radiator was replaced recently I'd sure like to see you check the coolant level (cold) in the rad. (yes, you'll have to remove the plastic cover over the rad and condenser). The coolant level should be right up to the bottom of the rad fill port.
You should verify that the thermostat has not failed in the open/near open position which will cause a very long warm up and/or cooler than normal coolant temps, and a lack of heat issue like you have. Modern vehicle ECMs do monitor the "time to get up to operating temp" (or similar term) and if this time is not within limits the ECM will set a code but I don't know if the ECM turns on the the Engine Check Light as well. After a cold start and after five minutes or so you should feel the top radiator hose (the engine return to rad hose) get warm/warmer/really warm with time, and the lower rad hose (the rad to engine hose) should also feel somewhat warmer which indicates that the thermostat is opening/opened. If the upper rad hose doesn't really ever get to the fairly warm stage in about ten minutes and the lower hose seems to stay pretty much cold then the thermostat may be stuck open. Has the coolant temp gauge been reaching about the mid-scale range?
You still need to verify that the temperature mixer door servo/motor is operating when the temperature selection is changed (in other words, verify that the mixer door is not stuck in the cool/cold position). After a cold start and with the system in "Auto Mode" the fan should not operate for two or three minutes (so as not to push cold air into the car) but after that the coolant should have warmed up to a programmed temperature and the fan should run. In "Manual Mode" the fan will not have the delay in operation.
Your photo of the coolant in the expansion tank looks low to me but maybe it's just the angle or my perception but it does look low compared to my car which is about an inch below the "F" mark as well. If you don't find anything conclusive with the items above, and because your radiator was replaced recently I'd sure like to see you check the coolant level (cold) in the rad. (yes, you'll have to remove the plastic cover over the rad and condenser). The coolant level should be right up to the bottom of the rad fill port.
#12
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Awesome thank you very much for the help on this i am going to drive up to where the car is parked in a little whyll and i am going to check the coolant level cold see where the level is and then start the car let it run for about 15 to 20 minutes and see where the level is then and ill check the top rad hose see how warm or hot it gets and also check the mixer door like you mentioned see if i can hear the motor trying to engage when i switch controls on the heater control see if i hear anything
i willd o this thank you
I have a scanner that reads the temps and can keep track of the time of how lng it take the engine to get to proper operating temp i have a OBD-II scanner that has this in it i belive.
also i don't knotice any issues with the temp guage getting up to proper level
i willd o this thank you
I have a scanner that reads the temps and can keep track of the time of how lng it take the engine to get to proper operating temp i have a OBD-II scanner that has this in it i belive.
also i don't knotice any issues with the temp guage getting up to proper level
Last edited by ThumperPup; 12-08-16 at 09:09 AM.
#13
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Yes, air mix door is a likely culprit, especially if the car is using a Denso controller. They have a habit of failing. If it has its own fuse, checking it couldn't hurt. Do you ever hear a sound from under the dash that sounds faintly like a cassette player running?
#14
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Yeah but the car has 2 doors, because of 2-zone climate. Both failed?
#15
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I was back out there today and i turned the car on i didnt turn the heat on i turned the car on and turned the the Vents and AC Heater off then about 15 minutes latter i went back to the car i checked the top rad hose it was good just how it should be had some preassure in there and some heat. check the cooland level in the overflow bottle it was just below Full like 1 inch maybe a little less below full.
i got in the car turned the Heater on put it on high and hot ear was coming out.
No Problem this time.
i also had my scanner i checked with it was saying that the ETC Temp was at 184 without the heater on and then when i turned the heater on it took the temp down to just below 177
i also switched all the modes i i was able to her the mode motors runing from vent to floor floor to defrost i ran the temps from Hi all the way to low and then low and dialed it all the way back up to Hi an dit adjusted just fine.
So am i correct in thinking if it was a heater core it would be flogged and would not be intermittent.
If it was the thermostate than the engine would either over heat or not heat up at all.
and if it was a blend door actuator then it would adjust from one mode to the other
and if it was the interneal temp control or the hard temp controls on the radio unit than that wouldn't work
so am i thinking correctly here that yes it is the Heater Control Valve that is the issue and perhaps the other night when i tried it it was like 22 degrees outside insted of the 30 it was today and it just wasn't unsticking maybe mositure in there or something ?
i got in the car turned the Heater on put it on high and hot ear was coming out.
No Problem this time.
i also had my scanner i checked with it was saying that the ETC Temp was at 184 without the heater on and then when i turned the heater on it took the temp down to just below 177
i also switched all the modes i i was able to her the mode motors runing from vent to floor floor to defrost i ran the temps from Hi all the way to low and then low and dialed it all the way back up to Hi an dit adjusted just fine.
So am i correct in thinking if it was a heater core it would be flogged and would not be intermittent.
If it was the thermostate than the engine would either over heat or not heat up at all.
and if it was a blend door actuator then it would adjust from one mode to the other
and if it was the interneal temp control or the hard temp controls on the radio unit than that wouldn't work
so am i thinking correctly here that yes it is the Heater Control Valve that is the issue and perhaps the other night when i tried it it was like 22 degrees outside insted of the 30 it was today and it just wasn't unsticking maybe mositure in there or something ?