2nd Gen Non-Engine/Transmission A/C works fine, then fades out--why??

[Warhorse]

When I start my truck and turn on the a/c, it blows fairly cold and strong. However, after running for awhile (about 20-30 minutes), the air flow will fade out and then stop blowing all together--nothing comes out of the vents at all. It may take an hour before it starts working again. Also, if I stop the truck (to get fuel or go to the store), the a/c will not come on at all when I restart, even though it had been working fine until I shut the truck down just a few minutes before. No air comes out of the blower at all. Any thoughts? Thanks! (My truck is a '97 CTD 4x4)

 

[DennyDay]

Sounds like it may be a vacuum problem - - 1st check to see if the vents work when you rotate the knob on the dash - - -from dash to floor to defrost



Denny

 

[GAmes]

The vents default to defrost, so if the air is coming out there the next place to check is the actuator above the throttle pedal, it will have a yellow vac hose. If it won't stay up with the selector set on dash pull the hose and check for vacuum. If you have vacuum the actuator diaphram is bad. Be VERY careful when removing the arm from the lever it is attached to.

 

[BHanna]

Your freon may also be a bit low. A slightly low charge can get too cold and cause the evaporator to freeze up, especially if it's humid where you are.

 

[Matt42]

Moisture in the system will do the same thing.

 

[Matthug]

I agree sounds like the evaporator is freezing up.

 

[BILLVO]

If the fan clutch is bad it will do this but it should still work fine at road speeds.

 

[JoeBioDiesel]

If the evaporator is freezing up (building ice up on the outside) it prevents air from passing through it. Does the blower still spin with no air from the vents? If so, check for a frozen evaporator. If that's your problem, have a new expansion valve installed.

Joe