Help;
The car is an 89 300SE and yesterday the AC quit blowing air and nothing in the climate control system would work.I found the climate control fuse blown.After I replaced it and engaged the AC,it blew the fuse imediately.I can live with no AC while I trouble shoot the system but heat is coming out of the vents when the car is driven.Does anyone know how I can keep heat from coming out of the vents? I'm in Florida right now and even a little heat is too much.Thanks for any help.

funflyer:
The system is set up this way intentionally. The failsafe mode is supposed to be full heat with air up on the windshield. MB is thinking in terms of a failure on a cold snowy day and trying to maintain a clear windshield. They figure if the failure occurs in July in Florida for example you can open the windows. You can't just unplug the heater valve, as there is no power going to it now, this is part of the failsafe; no power means heater valve is open, not closed. You could maybe get something to pinch off the heater hose; either side should reduce the heater core temp after a few minutes, the heat should dissipate. The easiest place would probably be in the area of the aux cooling pump on the right side of the engine down low in the engine compartment. The best way would be to get one of these ratcheting type pliers that are intended to pinch off hoses, this would be less harmful to the hose then using say a vice-grips, as the special pinch-off pliers have smooth jaws so shouldn't do any damage to the rubber like a jagged vice-grips jaws.
Hope this helps....
Gilly

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Thanks Dan;
Although I was wishing for a great dashboard fix for my problem, your' answer was helpful and enlightening about how the system works.Right now the weather has gotten cooler and I try to do all my driving in the morning which helps a lot but when the normal hot weather returns, I will be pinching that water line off till I can figure out what's making the fuse blow.Thanks again.

Other than fixing the problem, due to this fail-safe condition, this is the quickest and easiect fix I can think of. Plus then after it's fixed, you'll have one of those nifty pinch-off pliers. You may have something else that will work, maybe a small wood clamp and a few small pieces of wood?
Gilly

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