Intermittent loss of air flow in vents

The blend door actuator can be causing it, but can I ask if the low air flow happens with both AC and heater? Here is a guide that can help:

https://www.2carpros.com/articles/low-or-no-air-flow-from-vents

Please run down this guide and report back.

Cheers, Ken

I do not remember it happening with heat but it takes a while before the force starts to dwindle and I was not driving it regularly last winter. The difference side to side is there all the time. I do not have a cabin filter and cannot see any obstructions to the intakes; as for the blower motor, the sound of the force does not change, just that it is no longer making it out of the vents. Is there something on the AC side that would freeze up and prevent flow out of the vents? We occasionally get a drip in the passenger floorboard so the drain line is on my list to check, just have to find a wire coat hanger (no easy task, lol).

Yes it does sounds like the evaporator is icing up which causes the air flow to slow down. That is because the AC needs to be recharged. Here is a guide to help you charge the system and a video on how to unclog the evaporator drain:

https://youtu.be/uZrQCGwXfek

and

https://youtu.be/q9_MZiS2_NE

Please run down these guides and report back.

Cheers, Ken

The AC was just serviced this summer by my usual shop, it has actually been doing this ever since they repaired and charged it. I am not getting any real amount of water, just an occasional drop or two. Would that still be the drain line?

Yes it will be the drain. I think we should check the pressures of the AC system it sounds like that is the problem. Here is a guide to help:

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Let me know what the pressure readings are.

I do not have the kind of equipment to check the pressures, but I will have my mechanic check it since they did the original repair. I just put in the new blend door and the motor moves it all the way down (full cold) but not all the way up (full hot; see attached picture). Is it supposed to stop there?

It could it would still have air flow the fact that it only does it with the AC on after long time on tells us the evaporator is icing up. What happen to the heater box? Looks like you did a modification?

The only thing I have done is cut open the plastic to get to the blend door. So the blend door is supposed to stop only three quarters of the way up when the temperature knob is turned all the way to the hot side?
Also, I got under the car to find the end of the drain line and cannot see it. I know it’s there from the tell-tale puddles but I can barely see the firewall from the top side, let alone the bottom.

If the system is auto air then yes the blend door will go to the position and then adjust while in operation. It will not cause low air flow. The tube should be at the fire wall down low on the passenger's side.

Mine is manual, single zone.

Is it auto air? Do you set the temperature? or just hot and cold?

Just three knobs, hot to cold, speed and vent selector.

That is a manual system so the door should go all the way over. Can you remove the blend door actuator to see if you can move the door by hand?

It moves fine by hand and will go all the way up; got a new actuator on the way.

Okay let me know what happens.

Will do! Any special procedures for connecting the new actuator to learn correctly?

Nope should be plug and play.

New actuator is on and it takes the door further up. Of course, now it’s too cold to need the AC but I’ll get the pressures checked this week.

Sounds good please let me know.

My middle console vents still do not blow evenly; passenger one is pretty weak compared to driver’s. The other face vents blow fine. Is there something else I can check for that?

That would be a vent issue at the distribution. I would look for a vent tube that has split or has come off the vent housing. Use a flashing and look down inside the vents to see if there is something disconnected.

Finally got my mechanic to check the AC, apparently it was a little low on Freon. Hopefully that takes care of the freezing up but will not know until spring!

Nice work, we are here to help, please use 2CarPros anytime. Let us know what happens.

Cheers, Ken