I have a 2003 Lincoln LS V-8, and recently on a long trip I noticed that air was no longer coming out of the A/C vents after being driven for some time. I could hear the fan blowing but no air was coming out of the vents. Next I turned off the A/C and drove for several minutes before I turned it on again. This time air could be felt from the vents and it was cool.
My theory is that the refrigerant is low and the coil is frosting up. Does this sound logical? If it is low on refrigerant, is this something I could do myself, or does it take special tools and equipment to do?
I suggest you have an A/C specialist check it. There may be more wrong with it than just that. Get 2 opinions it you can, I have found that A/C repairs are one of the biggest rip-off area in automobiles.
A low refrigerant level can very well cause the evaporator to freeze up and restrict the airflow. This can be checked by looking underneath the right front of the car when it’s acting up. You should see a condensation drip. If not, the evaporator could be frozen up.
I assume your vehicle has the EATC (Elec. Auto. Temp. Control) and a problem could exist in that feature. You can perform a check for codes by doing the following.
With the engine warmed up depress bot the OFF and FLOOR buttons at the same time. Let up on them and within 2 seconds depress the AUTOMATIC button.
There will be 20-30 seconds of gibberish followed by some code numbers being spit out. The system does not have memory like the engine computer so everything will be real time.
Exiting the test can be done by depressing the COOLER button.
The kicker to this is that sometimes vehicles leave the factory with false codes in place due to testing procedures so one has to really think about what is being presented and whether it jives with the problem or not.
It’s always difficult advising someone on A/C repairs as it can be somewhat dangerous to the individual and possibly harmful to the car.
Hope some of that helps.