HVAC Problem, No Heat, Water on Floor

[GeorgePM]

1997 JGC, A/C with ATC. Couple of issues, which may be related. First, have no heat on any setting. Coolant levels OK. Can feel warmth on the bottom of the Lower Housing. Diagnostic codes indicate the dreaded Blend Air Door. Second, water, not coolant, collecting on the front passenger floorboard. Maybe elsewhere, but haven't checked.

I have read the threads here on these types of issues. Dealer suggests that condensate drain has clogged and (1) shorted out the actuator and (2) is overflowing onto the floorboards. Fix is to remove whole unit ($1,000) and clean out drain. He happened to overlook the TSB recommended fix for drain cleaning by drilling hole in drain at floorboard. As it happens, that process has already been performed on this vehichle prior to my possession.

There are apparantly four doors that direct or affect airflow in the HVAC unit: (1) fresh air (2) Heat/Defrost (3) Temperature Blend and (4) Floor duct. #1 and #2 appear to hinge horizontally. #3 and #4 appear to hinge vertically. The parts diagrams I have found list three actuators: (1) Heat/Defrost, (2) Temperature Blend (3) Recirculating.

Question -

1. Which if any of these actuators are accessible without pulling the whole dash? And where are they located?

2. Can the actuators be tested in place to determine if they are functioning.

3. Which, if any, of the actuators can be shorted or damaged by condensate overflowing due to a clogged drain.

If you have read this far, thanks. And thanks further if you have any thoughts.

[xj31]

it does sound like the ac drain is clogged.If the hole was drilled in the case,and the rubber plug is there you can pop it out and blow air or use a piece of wire or something to clean it out.
as far as the actuator being shorted out,it probably is.that would be the blend door actuator.it is on the bottom of the heater case on the passenger side right in the center up close to the firewall.it is held on by 2 screws. you can just take it off and there is a white plastic piece that connects to the blend door.you can turn it a little bit each way and make sure the door moves.you probably need the actuator because since it is on the bottom of the case,water drains through it and after a while it gets kind of corroded and it quits working.by the way,nice dealer you got there.

[GeorgePM]

Great, thanks for the info. Will give it a try and post results.

[GeorgePM]

OK, Drain appears to be clear. Found the accessible Actuator on the passenger side. Appears to be Temperature Blend door. Was able to remove the Actuator. However, I am unable to rotate the door by the shaft. I appears frozen and I don't want to put too much pressure on it, not knowing what's in there.

Question - should I be able to manipulate movement of the Door via the shaft exposed from removing the Actuator? If so, any ideas on how to unfreeze it?

How much pressure (attempting to manipulate) can it stand?

Thanks in advance.

[xj31]

the only time I have ever seen the blend door not be movable is when someone put it together wrong,or if something is broken.everything is plastic so it is kind of hard for it just to become frozen. it sounds like you might have something serious going on.you should be able to move that door by hand.it doesn't move much,maybe about 30-40 degrees of travel,but you should be able to move it.

[GeorgePM]

Thanks, if its all plastic, I will be measured in how I deal with it. I intent to check the operation of the Actuator while its off, and try to jiggle and finesse the Blend Door to see if I can sense what is impairing its movement. Hate to give up too easily on what could become a $1,000 repair to pull the dash. Will post an update