Replaced The Mono valve and now have heat!!!

However The heat seems to only be stuck in defrost and won't blow warm out of the rear seat vent...

Anybody ever seen or heard of this?

Thanks

The system defaults to defrost if it has any leaks. And, if it's original, you'll have one, or more than one, failed vacuum pod in the system. The leaking pod prevents the system from functioning and you only get air from the defrost outlets.

Plenty of info in the archives on how to test these systems and replace the failed pods.

Pray that the center vent pod is still OK...........

Boy do I remember my center vent pod. I have a permanent scar on my right hand when I installed it.

Also, the rear vent that is on the center console will only blow cold outside air. No heat will come from it. That is the way it was designed. Now on the other hand the rear seat vents that are under the front seats will blow heat when you get your vacuum leak fixed. I agree that you have a vacuum leak somewhere or perhaps a CCU failure. The default setting for your car is defrost vents only.

John

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John
1986 300sdl
1985 380se

Yeah, I think this is going to need some time put into looking at how to fix it..

But it still gets warm so i can continue to drive it and not have to give it the rest of fall off...