Dear Forum members,

Recently I've face with heating problem: passenger heating working perfectly but drivers not working at all. I have unplug coolant circulation valves (see picture) and found some oxide on contacts. I've clean the oxide using contact cleaner and plug contactor back. For couple minutes driver side (as well as passenger) start working as it should work but then error repeated. Now again heating works only at passenger side. Also while air circulating fan is working sometimes it completely shut-off for couple minutes and then return to operation again (no matter what regime is selected heating or cooling). Can you please advice if problem in heater core temperature sensors or i should replace coolant circulation valves?


heater core temperature sensors

coolant circulation valves

coolant circulation valves

coolant circulation valves

 

Iskender
Welcome to the forum from Baku Azerbaijan....
Before we attempt to correct your heating problem, try this as a possible solution to your heating problem by taking these steps

1. Start your car
2. Adjust the interior heater controls to these settings
   1. Set the thumb wheels on the highest heat settings to maximum red
   2. Set the fan speed to maximum speed
   3. Exit the car and close the doors, do not open the windows
   4. Permit the car to run for 20-30 minutes
3. ​​​​​​​After the run time, enter the car and turnoff all of the heater settings
4. Adjust the heater controls to your normal settings and turn the heater to the #2 setting speed and see if the vents work properly

I hope this works for you; it has worked for me in the past...
Dennis
​​​​​​​DTMenace

 

While it is common for the heater valves to stick, they seem to usually stick open, not closed. I am thinking your issue is in the control console. This can also explain the fan speed problem. (Fan speed problems are often the "blower motor resistor" but I get the idea your fan and heat issues are related.)

The PDF below may help you.

 

How often do you have to do this? It has worked for me too. Why do you say do not open the windows?

 

Leaving the windows closed with the heat on has a tendency to remove a lot of humidity (it is always good to remove excess humidity in a vehicle, right?). OR, It'll allow the systems sensors less time to fully settle down without any outside air temperature influence (which makes more sense being it is a dual zone system with a common ductwork return).


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Yes but you didn't read the entire thread. This is to unclog a stuck duo valve not for normal heating.

 

Yes, I did. I was answering your last question. I should have deleted the first question, I guess.....


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I don't see how sensors would apply here? We are just trying to unclog/unstick a duo valve with the hottest coolant possible just like if you were trying to unclog a slow drain at home with hot water. There is no ambient temperature sensor inside the Crossfire but there is one for the SLK320.

 

I believe there is at least one sensor in the ductwork for the system (but that wasn't the point). Never mind, you asked the question, I answered the part about closing the windows that was in the list from member DTMenace to a different member. Good luck.


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A sensor in the ductwork still would not make a difference with a stuck/clogged duovalve.

You sent me a PM a while back to stay out of each other posts, so let's go back to that agreement.

 

Guys, the sensors are on the heater core. There is one on each "side" and it senses how warm the air is that is flowing by in order to provide feedback to the climate control as to set the temperature of the air coming out the vents so that it (more or less) matches the setting on each ****. You can demonstrate this by settting the ***** at mid-point. Start a cold engine. As the engine warms, the duovalve will open less. The effect is, the air will rise with engine temp only to a certain point, after that, it stops rising as the feedback causes the duovalves to open less and less because the water is hotter.

There is no sensor, of course, telling the climate control what the temp in the cabin is, the system only regulates the temp of the air from the vents. I see no way for the BCM to know about window position, other than the BCM appears to know if hte windows are all the way up or all the way down. But there is no sensor to tell the BCM what the windows are doing, other than that. I don't have the manual near me, but I do think the Climate control is on the CAN BUS, I know the BCM is.

 

After thirteen years here, that is a new one to me. Iv'e never had the issue and Iv'e never heard of this fix. Perhaps cause running the system at max speed/max temp is common for me, as I drive around in cold weather with the top down and heat on max OFTEN. COme to think of it, often the windows are up to keep the heat in as much as possible with the top down.

Maybe I've been resetting something and didn't know it.

 

Dear Forum Members,

Yesterday i have tried this 20-30 minutes of "overclocking" - unfortunately no result. During test I have manually checked temperature of hot coolant supply tubes:



So supply tube was extremely hot as well as right (passenger) valve. However left (driver) valve was warm during entire 30 minute burn-out. Same for tubes connected to valves outlet which connected to heating radiators:



As you can see from above picture top tube (driver) was warm and bottom tube (passenger) was extremely hot. When I've stop heating and return temperature back to normal, bottom tube (passenger) cooled to warm condition. Next I 've disassembled HVAC unit and found nothing strange there:




I've even manage to increase contact between 2 circuit boards as it were described in "Climate Control Fan Speed Fix" .pdf file. Could you please let me know my next steps for problem solving?

Highly appreciate your support - thank you all

Regards,
Iskender

 

That my fellow member, is a TWO WAY STREET, if it at all happened (as I do not remember that 'issue' or PM). Funny, openly it seems you rub quite a few the wrong way. No need to reply, as since you do not wish any input from me regarding what concerned another member's post (and your post), so be it. BTW, if a PM was between us as you stated, maybe you should have just PM'd again? I'll just 'BLOCK' you, so you can rest in peace (if that is possible).


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Iskender, have you tried this; Leave the driver's side connector off the 'duovalve'. The valve should go to 'OPEN' (normal failsafe position). IF it does not, you have a clog in the return line somewhere OR a stuck valve. That should give you a more complete picture for that section of the system. IF it does get the driver's side hot (very hot if car is fully warmed up) then you may be getting a 'signal' to the valve to 'CLOSE' it. Do this at least twice (make sure the car is cooled down completely before doing the second try) to make sure it isn't an anomaly. Come back in to let us know your findings.


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Double Post


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Actually, as a moderator, I've never once had a message sent me about Ron.
Iv'e been asked three times now, what can be done about YOU.

 

Outside air is always coming into the cars interior otherwise we could die from the lack of oxygen.

 

Yes, and as you may know there is always a 'minimum' designed percentage of 'Outside air' in every ducted HVAC system by engineers. More so as a rule factored into vehicle systems due to the close proximity of exhaust gasses.


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Well, since you asked... Nothing, although I am sure you're looking for any reason. Anyone who would send PM's with those disgusting hate filled words, to which I replied in kind, confirms you and I should never again meet. For the record, I saved the entire transcript before it disappeared (like some of my posts, and possibly likely, this one).


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