2nd Gen Non-Engine/Transmission heater vents

[Bob Chociej]

has anyone had the problem of the defrosters shutting down. the fan motor is running, but nothing out of any of the vents ???????????????????????????

 

[Bob V]

Check for a vacuum leak

 

[SWC]

I have had that situation and I believe it is the evaporator core icing up. I am not sure what causes this but higher humidity seems to make it happen more often.

All of the air going through the cab ventilation system goes through air conditioner core. When you notice the air not blowing out of any vents turn off the a/c compressor. On my truck the only way to do that is to have the air blow out of the floor vents only. (I believe this is the one position that the a/c is off. ) This would take up to 5 minutes depending on how hot it was outside.

This problem has been discussed before. Someone who knows more can explain better then me why this happens.

Stan

 

[charlessmith]

If the evaporator core is icing up, it's an A/C problem. I think it's caused by low refrigerant, but I am not certain - not being an A/C technician.

Get your A/C serviced and the problem will go away.

That being said ... if air comes out only one place no matter where you turn the control knob, then it's probably a vacuum hose problem. if a vacuum hose is leaking, then none of the actuators will work to redirect the air.