wpgshark

1989
New blower motor,
New comb flap actuator
All others believed to be operational.

I'm getting really poor airflow when in AC mode. When I remove the rubber connector on the blower there is a hurricane. When not in AC there is at times great airflow, I have no idea what set of characteristics are required for this to occur, but it is interesting when it does.

There is virtually no airflow out of the door vents, except during those at periods of good airflow mentioned above.

Before I replaced the comb flap actuator it was worse and the evaporator would freeze up. I just did the actuator, I haven't driven it long enough to determine if it still freezes up.

All I can figure is that it has something to do with the mixing motor, nothing else really affects the air out of the center vents, except the manual flap which is open. Although I've checked if it moves between full cool and full heat, it does, I don't know if it responds properly.

I've tried all of the discharge settings, no difference, and with the recirculation open, temperature all of the way to the left.

I've checked the forums for the diagnostic procedure and will commence same this weekend. However, I'm looking for any insight in what I'm seeing before I start.

Any knowledge transfer would be greatly appreciated,

Thanks,

Lance

The

The Forgotten On

Look in front of the evaporator to see how much junk has accumulated there. Usually it is a lot and can seriously impede air flow.

Remove the boot and check it just to be sure.

Leaves and stuff can also get into the box so you may need to split it. Only do this as a last resort though.

wpgshark

Evaporator is squeaky clean.

The confusing part is that at times the airflow is good, meaning the coil, fan and air box are all capable of working, for some reason they don't when the AC is on.

Thanks for the suggestion.

The Forgotten On

Sounds like your evaporator is just icing up. Test your freeze switch to see if it is working correctly because it sounds like it has failed.

They are a mechanical part and the brass diaphragm inside wears out or the fluid in the capillary tube has leaked out.

wpgshark

That is a good point and I will check the switch. I was concerned about that and played with it today.

When I've frozen thin the past, when I shut off the AC , I would still get cooling as the evaporator thaws, no cooling today. Also if it was the evaporator freezing I should be getting airflow that goes down slowly as the coil freezes. I'm getting next to nothing from the second I push the AC button.

I have added the check switch to my list for this weekend.

Thanks for the suggestion.

GregBBRD

Unless you enjoy pulling the center console, the entire dash, and the entire HVAC box, I wouldn't allow the evaporator to freeze too many times.

Freezing the evaporator into a solid block of ice is asking it to crack and leak Freon.

PorKen

Does the car drip water when parked? Check/clear the drain tube for the A/C.

https://rennlist.com/forums/928-foru...a-c-drain.html

dr bob

Fixing the comb flap actuator is a good start. Pull the little grill/flaps at the center vent outlet, look and see that the comb flap is indeed retracting. A problem in -any- of the other vacuum-operated pieces will come back to haunt the action of all the others.

The operation of the mixing motor is more related to temperature than flow, unless it's stuck all the way and the wrong (hot) position. In my car, I can hear that little motor running when I move the temp lever back and forth. In addition, there are little microswitches at the end of travel both ends that normally cause the setting motor to move to end-of-travel when the slider is all the way hot or cold, regardless of the readings coming from the temp sensors or the rheostat potion at the temp slider.

wpgshark

Car drips water when parked.

This morning I messed around with the controls and became more confused.

Started with AC switch off panel cooling, temp cold but not to the full left, similar airflow to with AC on.

Moved the temperature switch full to the right, no real difference in airflow.

Moved it back to the previous position and airflow went up.

Pushed the AC switch in and airflow almost immediately went down.

I'm going to snake my camera into the box through the door vent to take a look.

Thanks for all of the help.