1996 mercury couger

Havc a/c work/ heater work but stuck on defrost had to change.the blower wire and no over vents.will work on stuck on defrost vent upper. Thought was automatic cotrol box it.wasent.it but wasn’t wire to blower

Wow, that is a cryptic description.

If I decipher that correctly the car is stuck on defrost. There is a door in the ductwork that directs air where you set it. That door isn’t moving. It is moved by an electric motor than no longer works. Find it, replace it. Good luck finding parts.

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I agree with Mustangman, but I think the mode (defrost) door actuator is vacuum controlled on your vehicle and if it goes bad or loses vacuum the default mode is the defrost vent… Should have some hard plastic lines going from the HVAC head unit to the mode actuator, check it to see if broken anywhere, you can also hook up a manual (hand) vacuum pump to the mode actuator and to see if it works…
It should look like this…

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OP, if your engine’s idle quality seems to be suffering, pretty good chance the problem is a leak in the vacuum hose or one of its connection points mentioned above. The actuator’s diaphragm could have sprung a leak as well, similar engine symptom, but the vacuum leak is at the actuator, not at the hose.

My daughter had a '99 Cougar (not Couger) and she had the same problem after some work was done on the car. A vacuum hose was severed underneath the car as I recall, between the heater and the engine compartment.

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ok thanks for all help i found it was small broken vacuuam line thank for help

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