Climate Control sensor

[bigasotonuk]

Hi,
As some of the forum members know I have had an ongoing problem with my Climate Control, basically it does,nt throw out cold air.
I believe i have chased the the problem to a faulty Heater core sensor (I plan to get it plugged into STAR to get this confirmed), a grand total of £10 from MB.
Now I have looked at various sources of info, and it appears i may have to remove the complete heater box assembly from the car to change this sensor, which involves removing just about everything around the dashboard area and even dashboard and steering column inside of the car.
Can anyone tell me if this is correct or can i replace it without this enormous amount of removal.
Any suggestions greatly appreciated.

 

[roofless]

i dont know if this is of any help to you as you seem to know your cars rather well http://www.benzworld.org/forums/w202-c-class/1387534-hold-down-rest-button.html

 

[bigasotonuk]

Yes i have seen this before and thats how i suspect the heater core sensor but i have not seen it mention anything about resetting before so I will study this with interest, many thanks. But if this sensor does prove to be faulty does the car really need to be stripped to gain access to it, does any one know or offer any advice?

 

[television]

Sensor's are not easy things to measure Andy, but they do have some readable characteristics, can you get to the other end on the wires, if you can then the readings could be compared to a new one

 

[bigasotonuk]

Hi Malc,
Yes i believe the sensor in question can be measured from the plug of the control unit, and therefore could also be bypassed and taken out of circuit at that point, to then hopefully prove correct diagnosis. In fact i used the link above in roofless's post above to try to diagnose the fault but my car gave a unrecognised fault code "41(small temp circle) then the number 9".
As the temp sensor we are talking about is so cheap i would be prepared to replace it just for elimination purposes.
Anyone know whats involved in changing this sensor?

 

[television]

I will see what I have Andy, prompt me if I forget

 

[bigasotonuk]

Many thanks Malc your a "STAR".

 

[television]

I find this post interesting for I had a 129 that got cooler and cooler the further you drove, but did not think too much about it at the time.

We have since in the last couple of weeks 2 members that have fixed this fault by changing the sensor, though it is easier on a 129. They can be wired in different ways to get different effects but its still that sensor the fails

 

[bigasotonuk]

Yes reading the threads regarding the faults on the 129 SL A/C (though the 129's it appears to be the Evaporator temp sensor) is what made me scrutinise the readings from the sensors on the diagnostic menu, it is saying with the car cold that the heater core sensor is reading 50 degrees or so which cannot possibly be right hence leading me to suspect it to be faulty.
If I do take it all apart i will be replacing the Evap. sensor as well.

 

[MB TECH WARRINGTON]

Hi,
As some of the forum members know I have had an ongoing problem with my Climate Control, basically it does,nt throw out cold air.
I believe i have chased the the problem to a faulty Heater core sensor (I plan to get it plugged into STAR to get this confirmed), a grand total of £10 from MB.
Now I have looked at various sources of info, and it appears i may have to remove the complete heater box assembly from the car to change this sensor, which involves removing just about everything around the dashboard area and even dashboard and steering column inside of the car.
Can anyone tell me if this is correct or can i replace it without this enormous amount of removal.
Any suggestions greatly appreciated.

not looked at your previous posts, but i take it you have eliminated the heater duo valve?

 

[bigasotonuk]

Hi,
I did originally think the duo valve could be to blame, but i do have temp control from high down to low but it just does,nt get cold enough, and when disconnected it defaults to max heat setting which i,m led to believe is normal behaviour, and if this was at fault i thought it would show some other more obvious fault.
What changed my mind regarding the fault being with the duovalve was the temp reading of the heater core sensor reading 50 degrees when the car was cold.
Is there a recommended test procedure for the duo valve so i can absolutely rule it out?

 

[television]

Duo valves like seat heaters etc work on a pulsed voltage, only seen on an oscilloscope.

 

[television]

I have 8 pages for you Andy and will get them off tonight, I have covered just about every item involved

 

[bigasotonuk]

Many thanks Malc your a STAR, I,ll look forward to reading these.

 

[television]

8 Emails sent Andy and it should be all you need,it has to come out and not other way, just ask if you do need more

 

[bigasotonuk]

Hi Malc,
No mail as yet, did you send it to this address Mounttemple@aol.com?

 

[television]

Yes and it has not come back

 

[bigasotonuk]

Hi Malc
still no mail, this seems to always happen when you try to mail me. If you could PM me you email address I,ll send one to you so can attach the file and send it back via reply, i seem to remember this working last time.

 

[television]

Hi Malc
still no mail, this seems to always happen when you try to mail me. If you could PM me you email address I,ll send one to you so can attach the file and send it back via reply, i seem to remember this working last time.

Take it from here

m.wecall.co.uk

 

[bigasotonuk]

Crikey your quick with that keyboard sir.
I don,t know what you did differently Malc but i now have the documents,
Many thanks.