Heater not turning off

[ronhugh]

I have a 1990 230TE which is a stalwart vehicle. Just encountered a problem with the heater always blowing hot air (on both sides of interior). Is there a 'heater control valve? I have read that there is a solenoid switch which should automatically close when the ignition is turned on. Even in this not very hot summer, the heat is just too much.

RonH

 

[television]

Welcome Ron the the forum.
This is normally the duo valve either failed or stuck and it is the first thing to try, 53 in the link

http://www.detali.ru/cat/oem_mb2.as...+++717.413&CT=F&cat=15U&SID=83&SGR=180&SGN=04

 

[ronhugh]

Thanks malcolm, will try that

Ron

 

[bigshineybike]

Is it ever the electronic control panel?
I think I have checked all the clunky bits.
This little circuit board is suspiciously unmentioned elsewhere in these forums.
mine looks like it may have some water damge like the board has been damp at sometime, i am waiting for a new onefrom a breakers but not so sure its going to help.

 

[television]

Is it ever the electronic control panel?
I think I have checked all the clunky bits.
This little circuit board is suspiciously unmentioned elsewhere in these forums.
mine looks like it may have some water damge like the board has been damp at sometime, i am waiting for a new onefrom a breakers but not so sure its going to help.

Yes it is and we had one this week where the control box was dead

 

[Bathbluesman]

Hello Malcolm,
just cutting in on this message. Can one unstick one of these duo valves as I have the same problem on a 1991 230 ce. If they can't can they be bought?
Dave

 

[television]

There are post in the DIY section on dealing with these, most can be bought,,many completely re build them, they always fail in the hot mode

 

[Alex Crow]

and to add to that, sticking valves are less common than ones tending towards open circuit! if you have a multimeter, test the resistance of the solenoids - central pin common to both.....