I believe my 2004 Mercury Marauder blend door is not working - again. This will be the second time in 3 years. Symptoms: Although I had it only set in A/C mode, it was cycling on its own between the dashboard vents to the defroster vents for 2 days. Today it will only blow through the defroster vents. Is this something I can repair on my own without too much trouble?
Country: United StatesMake: MercuryModel: MarauderYear: 2004
Hi, I’m Chris. Welcome and thanks for asking your question!
The blend door controls the temperature output, not the direction of the air flow. Is this the same issue you had prior?
Do you feel comfortable doing some repairs and tests inside the dash?
You will need to buy a hand held vacuum pump with gauge to test.
Do you have auto or manual climate control, most likely auto?
I have been very unlucky with the HVAC in this car and so I may be confusing issues. I did have identical symptoms before and was fairly sure he said it was the blend door motor, but maybe I am mistaken.
I have done work on cars before (replaced a water pump, done oil changes), but never pulled the dash.
I have automatic temperature control.
Brian the dash HVAC has multiple mode doors that are controlled from engine vacuum and the control head. it defaults to defrost when you have lost vacuum, so I feel you have a leak causing all of this. Below are diagrams showing the vacuum routing and how to diagnose and how to access the components.
16 years experience with Mercury