bambam

problem is as tittle says.
whenever i try and use my heater since it its been cold lately it just wont throw any hot air. it will just blow air at w/e temp it is outside, which is ***** cold.lol
the AC works fine, i Think all fans work fine, just not sure why only heater wont work?
ive checked the fuse and its fine.. is the thermostat messed up or what could be wrong?
thanks in advance for any help

RoboCop

iTrader: (1)

Obvious question, but how long is your car running before you turn it off? Or better yet, is the engine temperature at operating temperature when you notice it isn't blowing hot air?

bambam

before i turn off the car??
yup it doesn't take long for engine temp to be at operating temp, even so heater wont work

RoboCop

iTrader: (1)

Just asking because 5 minutes in the cold isn't always enough to get a good heat buildup in the engine before it can start pushing hot air.

Esh Darkstar

If the thermostat (that's the device that controls the temperature of the engine) then the engine would either overheat or be slow to come to temperature if it ever did. Since you haven't reported either condition exists, we can rule out the thermostat. In the service manual there are about seven different things that it could be. https://www.scionlife.com/tech/manual/?manual=tc05_2017

I think it's safe to rule out a couple items like the A/C amplifier assembly but you never know. I'm going to assume you bought this car used and this is the first winter you've tried to using the heater. There is the possibility (very slim at that) that someone has either disconnected the heater from the coolant system or that there is an actual clog in the coolant lines that run to the heater coils. I would do a quick visual and trace the lines from the coil back to where they connect to the engine and feel if they were getting hot or not.

Just remember it's next to impossible to properly diagnose a mechanical problem over the internet with less than 100 words written on the problem.

bambam

ok so i guess it isnt the thermostat

[/quote] I'm going to assume you bought this car used and this is the first winter you've tried to using the heater.[/quote]

and yes ure right^^
so i would have to check lines connected to the water pump and the radiator for clogs and hope thats the problem?lol

mrjtang

this has nothing to do with the thermostat. the thermostat controls the release of water to cool the engine down. it doesn't necessarily control the cabin temperature.

i would check fuses first.

Esh Darkstar

I'm going to assume you bought this car used and this is the first winter you've tried to using the heater.[/quote]

and yes ure right^^
so i would have to check lines connected to the water pump and the radiator for clogs and hope thats the problem?lol[/quote]

I think you misunderstood what I meant, I wouldn't check all the coolant lines I would check the ones running to the heater element in the cab. First just make sure they are there and then second I'd feel there temp after the engine was at temperature and the heater set to max. That would give me an idea if the coolant was actually circulating between the coolant system and the heater element and maybe some idea on what's causing it.

Understand I'm old and crusty and think myself as a mechanic. I might find something doing that or I might just be wasting my time.

Follow the service guide that I posted a link. It's actually made by the people that work on the car and it's their troubleshooting procedures.

Just keep in mind that at some point it will be better off taking it to a mechanic from a time aspect. Your time is money even if your not getting paid for it and at some point you may spend more in time than what it would cost to just have it fixed by a trained professional.

TheMuffinMan00

iTrader: (2)

I have seen the mechanical part that opens the coolant flow to the heater core (the part inside the car that he is referring to) come off or never get put back on by a mechanic who worked on it last.

That is one thing to check as well. you can look under the hood while someone switches the air from hot to cold to try to see if the cable that is going to one of the coolant lines on the back of the block to the firewall is actually moving. If it is not that could be your issue. If it is check the temp of said hose to see if it is getting hot. If not you probably have a clog somewhere.

bambam

ok so ive been real busy lately and it hasnt been cold, but i want to fix this problem either way
ive checked every fuse one by one both in the fuse bos n under the dash, so no blown fuses.
i even took apart the HVAC tyhinking the **** might have been broken or something but nope.
i tried looking for those lines you guys have said but i have no clue which ones or were they are located. any help finding them?lol

Esh Darkstar

Look on the drivers side of the engine block. Towards the firewall you should see two 3/4in hoses running into the firewall. Those are the coolant lines that put heat in the cabin.

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bambam

ok so i found them and their both plugged in, i also checked to see if they got hot when the engine was on and they did,
also when i switch form cold to hot air on the **** i believe it controls some kind of servo motor to change the temp right? i tried hearing for it to see if it moved and i heard nothing, could that be the problem?

AWilson013

Turn on your headlights so that the **** for your temp selection lights up. When it's all the way hot, is it still showing blue?

bambam

no its never been blue on the hot side, always red.
why?

AWilson013

Well, if it stayed blue it could indicate that when you turn the ****, it's not really registering that it needs to change the temp. But since it turns red, disregard.

AWilson013

Check out page 34 of this link... TC Electrical Take note of item "D2" as this is your "Air Mix Control Servo Motor" which controls the hot/cold air mixture. I would ensure first that it's plugged in.

I would then test the resistance of the Servo motor itself.

Take your multimeter (get one if you don't have one) and set it to measure ohms.


Connect Yellow (SG) - Purple (S5) Should read 4.2 to 7.8 kΩ
Connect Yellow (SG) - Gray (TP) Should read 3.4 to 6.2 kΩ
Connect Yellow (SG) - Green (TP) Should read 0.8 to 1.6 kΩ

If the readings are not within the standards, replace the air mix control servo motor.

bambam

oh ok,

im planing to check the servomotor next, hopefully its that and i fix this already.
thanks for the help!!