Heater qustions - New to this forum...

[Macau_C180]

Hello to all, im a new user, and i own a 1997 C180 Classic.

I have some questions about the heater, i dont really need it, but i would like to have everything working. My AC is very very cold seems that the AC pump is always on, its a new pump, and when i turn the dials for the temperature control on both sides, no difference, always very cold, and nver hot air. Can it be the duovalve? Or can it be the control panel in the dash? My car have the manual AC.

Thanks

 

[BlackC55]

More likely that the duo vale is faulty. Someone here did a "how to" about cleaning it. Try that first.

 

[Dieselman]

I would say it's unlikely to be the duovalve as when they fail it's normally with the heater stuck full on as that is the relaxed position for the valves.

Disconnect the duovalve electrical connections and see if the heater goes hot, it should do. This would indicate they are being held shut.

More likely the heater control panel is faulty.

 

[grober]

I think for your age of car your heater control/flaps may be vacuum diaphragm operated -controlled by electrical activation. Check that you have no vacuum supply or activator leaks. As dieselman says the problem probably lies within the heater unit itself inside the car. There are quite a few posts on this on the forum. e.g. http://mbclub.co.uk/forums/showthread.php?t=27565&highlight=heater+vacuum+controls

 

[Macau_C180]

Thanks for the tips, i will check on that when i have some time, right now its very hot here, and the super cold AC is fine