Mercury Repair Questions? Ask a Mechanic for Answers ASAP
It changes on the display but the airflow doesn't change thru the vents
ok will do
When the air blows out of the dash, does it only blow from defrost?
First is the source vacuum line to the climate control system. The air flow distribution control doors are moved by vacuum operated motors. If the vacuum line that goes to the climate control module has no vacuum on it the system defaults to defrost only.
Second is the climate control module itself. The vacuum distribution is handled by the climate control module (the module is the control panel you use to select the climate modes). If the part of the module that handles vacuum distribution fails you would lose control of the doors. The self test will not pickup vacuum issues, it only checks for electrical problems.
The first thing I'd check is the source vacuum line. If you look under the hood it is the line that goes through the firewall into the dash. Make sure there is vacuum on it. You can also look under the dash on the passenger's side of the car. The vacuum line should be visible from there. The source hose is usually white, but not always. If you have good vacuum into the car, try disconnecting the battery for five minutes to reset the climate control module.
If none of that helps you need a new climate control module. 90% of the time when I see the same symptoms you have it is caused by a source vacuum issue.
Hope this helps, if you have any further questions do not hesitate to ask.