99 S70 2.4 55 ENGINE CODE

If your mode controller works for other options but not for front vents, the likely problem is a failure of the door actucator or linkage. If the mode seems to be stuck in defrost mode, the likely problem is a vacuum leak. The mode control runs on vacuum supplied from the engine intake manifold througn a thin plastic line. The mode switch puts the vacuum to different doors in the heater box to redirect the airflow. Each door is operated by a vacuum actuator. If the supply hose or actuator diaphragm leaks, that door will not operate. If the supply line from the engine or the switch itself leaks, none of the doors will operate and the mode defaults to defrost.

The Intrepid doesn't have a vacuum line. It uses a electric motor called a "blend door actuator". It's located on the underside of the heater box near the center of the car.

Defrost is the default when the controller is not receiving vacuum from the intake manifold. Look for the small vacuum line going from the engine intake manifold to the firewall and trace it to the control switch. If the vacuum line looks OK, try to pull the vacuum connection from the control switch. Then start the car and see if there is vacuum coming to the connector from the line that you traced from the engine. If no vacuum, the line has a leak--retrace to the manifold. If there is vacuum, your switch is probably leaking. You can buy a new vacuum switch from Ford or some parts stores. More questions, please let me know.

Intake air temperature sensor or circuit shorted. Look for sensor popped in on intake hose from air filter. If not connected or wires broken find & repair connection or sensor is bad. Replace.

Step 1 Unfasten wire harness to MAF (massive air flow) sensor located on top of the black tube leading from the air box to the plenum.

Step 2 Unplug the vacuum line located on top of the black tube. This simply pops in and out so you might need to be forceful, but apply common sense since it's a plastic vacuum line.

Step 3 Loosen band clamp with the screw driver at the top of the black tube that is attached to the aluminum air chamber that run to the plenum. Also, loosen the other band clamp located at the bottom of the tube closest to the air box. The idea is to remove this tube with the MAF sensor intact in between. Do not remove the band clamps, simply loosen them enough to wiggle off the tube and move it out of the way.

Step 4 Unclip both fasteners at the top of the air box and pull out and up to remove air box cover. Remove old air filter and if there's a good deal of dust and debris inside the air box, you could wipe it out with a rag or even vacuum it out with a shop vacuum.

Step 5 Insert new filter and replace air box cover. Make sure the retaining tabs are locked in at the bottom correctly. Refasten top locking clips to air box cover.

Step 6 Reinstall air tube making sure to replace top part back on correctly to aluminum air chamber. Not properly reinstalling this air tube will result in the computer of the car throwing a check engine code. On the bottom of the black air tube is a small tab and if tube is replaced properly should line up in a notch molded into the air box cover. Tighten band clamps with screw driver and reconnect wire harness and plug plastic vacuum line back in.

1. Unfasten wire harness to MAF (massive air flow) sensor located on top of the black tube leading from the air box to the plenum.
   
2. Unplug the vacuum line located on top of the black tube. This simply pops in and out so you might need to be forceful, but apply common sense since it's a plastic vacuum line.
   
3. Loosen band clamp with a screw driver at the top of the black tube that is attached to the aluminum air chamber that run to the plenum. Also, loosen the other band clamp located at the bottom of the tube closest to the air box. The idea is to remove this tube with the MAF sensor intact in between. Do not remove the band clamps, simply loosen them enough to wiggle off the tube and move it out of the way.
   
4. Unclip both fasteners at the top of the air box and pull out and up to remove air box cover. Remove old air filter and if there's a good deal of dust and debris inside the air box, you could wipe it out with a rag or even vacuum it out with a shop vacuum.
   
5. Insert new filter and replace air box cover. Make sure the retaining tabs are locked in at the bottom correctly. Refasten top locking clips to air box cover.
   
6. Reinstall air tube making sure to replace top part back on correctly to aluminum air chamber. Not properly reinstalling this air tube will result in the computer of the car throwing a check engine code. On the bottom of the black air tube is a small tab and if tube is replaced properly should line up in a notch molded into the air box cover. Tighten band clamps with screw driver and reconnect wire harness and plug plastic vacuum line back in.
   

Check for vacuum leaks. ie, vacuum lines them selves, the rubber tube that runs from the air filter to the throttle body. If it has a plastic intake manifold, possibly the rubber port seal gaskets between it and the engine. Lean codes are set when the PCM isn't monitoring all the air coming into the engine (vac leak) or low fuel pressure.

The secondary Air Injection system, this is basically an inspect and replace broken hose detail. Leave the inlet hose disconnected and start the engine. Listen and feel for exhaust hissing at the check valves.The check valve(s) will make like a gurgling sound as air is drawn in However , if exhaust is felt or heard replace the valve. Hope this works out for ya.

Does the air come out from the defroster? If you hear the blower motor and don't get any air from the panel, the car may have a vacuum line either off or broken under the hood. Check under the hood by the pass. side firewall and see if the vacuum line going through the firewall is off. Listen for a hissing sound around the area when the engine is running. There is a vacuum canister in the front bumper on the right side, it could be cracked.

I had the same problem...

There is a vacuum line that operates your selector switch, it is located under the hood, roughly in the center, up against the fire wall. If the line has leaks, your selector switch will not work and therefore all your blower doors will stay shut. Replace the line.