Defrost making things worse

[IIGood]

I thought the blend door issue was temperature related? My hot and cold work just fine...cold comes out cold, hot comes out hot...and the air is being directed properly.

 

[Number4]

With the blend door issue, you usually only get cold or hot air, out of any vent.
There is another door that gets its arm broke by the actuator that controls which set of vents the air comes out of.
Another door that breaks is the one for fresh air or recirc.

 

[stonerhino]

Well this is weird. The prior owner must have put some sort of grease or some rain-x product on the window. I cleaned half the window off and the half I cleaned the scum from, fogs worse than the one I didnt clean off.

The weather was exactly the same as the first time. Dumping rain, wet, and cold.

The insipid computer strikes again as it apparently locks out the compressor when below a specific temperature and the engine is not warmed up. Once the engine warms up, the compressor is allowed operation.

This is a very dangerous condition to drive in and very wasteful of fuel if I have to let the car idle for 10 minutes to clear a bit of moisture from the window.

 

[briwayjones]

With the fan all the way up how much of a force of air are coming out of the defrost vents? Because even in chilly humid weather cool air will clear fog off of the windshield if there is enough air flow.

 

[IIGood]

In my case it certainly seems like an adequate force of air is coming out. When I set the fan speed to 4, it certainly sounded like it was blasting the air out. But I really don't have anything to compare to...maybe it is a weakened flow and I don't realize it.

Can the ducts get clogged?

 

[briwayjones]

In my case it certainly seems like an adequate force of air is coming out. When I set the fan speed to 4, it certainly sounded like it was blasting the air out. But I really don't have anything to compare to...maybe it is a weakened flow and I don't realize it.

Can the ducts get clogged?

I don't see how the vents could get clogged other than mice or something building nests in there. And that would have to be in all of the affected vents. And of course I would think it would be easy to tell if that was the case. And not likely at all on a vehicle that is driven often. So I don't see how they could be clogged.

 

[IIGood]

I didn't think so either.

Does air get pulled in from the cowl area? Wondering if that area could have some kind of blockage...

 

[Number4]

The fresh air/recirc air door often breaks and falls on top of the blower.
You should be able to see the door when looking through the recirc opening behind the glove box. If you can't see the door, then it's laying on top of the blower. As it won't physically touch the blower, the blower will continue to operate, but will obviously be seriously hampered.

 

[stonerhino]

That is a thought on the recirculate door. I will check that.

But yeah the airflow is a bit lackluster out of the defrost vents. Ill snake a camera in there to see if somethings wrong.

 

[IIGood]

Thanks for the tip, I'll check mine as well. Sounds like that would be easy enough to check anyway.

 

[briwayjones]

The fresh air/recirc air door often breaks and falls on top of the blower.
You should be able to see the door when looking through the recirc opening behind the glove box. If you can't see the door, then it's laying on top of the blower. As it won't physically touch the blower, the blower will continue to operate, but will obviously be seriously hampered.

Hey [MENTION=226817]Number4[/MENTION]! Maybe you have an idea for a problem I have on my 2nd gen. There was one other guy on here that seemed to have the same problem but we never got a solution.

When using the defrost setting only, when I work the engine harder like going up a hill or speeding up to merge or something the air will bounce from the defrost and start coming out of the floor vents instead. Or a mix of the floor and front vents. Then when the engine gets back to being worked normal it will then return to coming out of the defrost vents only again.

 

[Number4]

No exact knowledge, but I'd presume it's all vacuum actuated.

So, there may be an issue with the vacuum under load. Or lack of vacuum allow for the issue.
Also, some vehicles will cut out the ac compressor when under a load to give the engine more power. (The compressor runs when the defrost setting is being used.). Again though, for the air to flow out of other vents, I'd think it would have to be a vacuum issue.

 

[briwayjones]

Thanks!

 

[IIGood]

I got home this evening and decided to check this out. Dropped the glove box and shined a flashlight in there to see whats up. I directed the light towards the grilled area above the blower motor and when looking through, it appears that the door is up. I saw the diagonal plastic lines back there so I'm assuming that's the door in question? I don't know exactly what to look for, or what not to look for. LOL.

On a whim I started the truck and fiddled with the fan speed controls and HVAC controls and watched that same area. Nothing changed...no movement of any doors or anything. Or would that not be affected if the truck was just started cold? I didn't let it warm up any before switching the controls around. Would that make a difference...does it need to be at normal operating temperature to see any movement of this door?

And I retract my earlier statement about the air flow being strong. While I had the fan blowing during this experiment, the air flow out of the vents did seem to be on the weak side. But maybe it's just me...you know, the whole "placebo effect" sort of thing...

 

[briwayjones]

I would think whether it warmed up or not should not change the way the door works.

 

[Number4]

The far right vent selector switch has 6 on positions. Max AC and 5 other options. The door only has two positions. Using Max AC, the door should be all the way to the back. This will recirculate the already cooled interior air back through the evaporator and out the front vents.
The other 5 on positions will cause the door to move forward and seal off the cabin air, only allowing outside air to pass.
So if you move the selector to Max AC and watch the door, then pick one of the other 5, you should see it move.

 

[IIGood]

I opened up the glove box again this afternoon while it was daylight out still and had another look. This is what I saw:

It appears the recirc door is closed to keep the fresh air out in this position, correct?

I started the truck up and went through the fan speeds...I did feel air coming out of the appropriate vents, and I switched it to each of the controls - defrost, floor/defrost, floor/upper, etc. When I switched it to MAX A/C, the door did not move. And as I switched it from MAX A/C to A/C, there was no movement either. It always stayed in the position pictured above.

I also did not observe any change in fan speed or blower noise when going between A/C and MAX A/C and back.

So I'm wondering if the door is stuck keeping the fresh air out.

As a side note, does anybody know what the small connector that's hanging in the picture might go to? When I dropped the glovebox it was just hanging there like that. I don't see another connector that it would go to...

 

[IIGood]

Another little update...

I drove my dad's 2005 Explorer XLT last night and tried the various HVAC settings. Fan speed, direction, etc. Mainly wanted to report that the defrost on his is just as powerful as mine on each fan speed setting.

So I guess it really isn't a matter of air flow after all in mine. Still wondering about the circulation door though.

 

[stonerhino]

Right now mine is in a shop getting the transmission rebuilt. I was on a drive to Richmond and it gave out. Rotten luck...

So back in the '89 LX Hatch I go.

 

[stonerhino]

Okay, so exploder's back in my hands with a larger transmission cooler and fresh fluids.

Going to take a poke under the dash to see if the door is even moving as in my mustang, I can hear the air diverting. This I cannot, but I do hear the distinct sound of a vacuum leak.

Also the guy that worked on my transmission pointed to me the plastic thermostat housing has a leak under pressure and recommended replacing it.