1999 SLK Heater Stuck on HOT!!

[DR1VER]

Hi

Having a bit of trouble with a '99 SLK 230k auto The heater blows hot whether the wheels are on hot or cold or anywhere inbetween.

I don't really know where to start but would like to think its a simple sensor fault.

Any help would be really appreciated

Thanks

 

[MBK]

Maybe your duo valve, check you got power goign to it using a voltmeter, as the duo valve defaults to hot when it loses power. Or it could be tha tthe duo valve is simply stuck open. give it a little tap on top whilst the dial is set to cold and see if this solves it if so then you can follow "parrot of dooms" little instructional on how to service your duo valve (it worked for me)

K

 

[renault12ts]

Don't worry. At least you'll have a long hot summer even if the rest of us don't.

 

[Aletank]

Does the blower/fan come on full power and you can't turn that down/off as well ?
If so it could be the Blower/Fan Regulator

 

[DR1VER]

Hi guys

Thanks for the help, the fan part is fine, its just that its always on hot. I'll give my valves a tap and let you know how it goes.