HVAC box help needed!!!

[BigTree]

Alright guys. First off the car is my 91 RHD JZA70 car.

The air from the blower motor only comes out of the vents. When I press a different selection on my control unit I can hear the motor moving but heat always comes out of vents thus I cannot defog my windshield. I went underneath my dash today and from my driver side (RH side) I saw this.

The red arrow is pointing to the arm that does not move with the motor. At first it was difficult to move; stuck in one position but I unscrewed the screw going to it and it can now move down and it moves back up by itself. After re tightening the screw it still can move down. Where it is in that position is as far up as it goes with me putting force on it. The blue arrow is pointing to the plastic piece that was disconnected from the motor so I hooked it back up.

Here I dotted red spots all over part of the motor that moves when a selection is pressed. I am wondering if it is supposed to be hooked up to the arm that does not move with the motor. I put a red dot on it also. I cannot see any way for the motor to connect to the arm but it looks like the arm definately has a place for something to connect to it.

Here I am holding this arm that does not move as far down as it can go with moderate force. When it is defaulted in its upright position heat comes out the vents quite strongly but when it is forced downward it does not come through the vents as hard and a very little bit comes through the defrost vents for the windshield.


Please help me out here guys I would really like to avoid pulling the dash to get the damn unit out in my hands to play with. Any and all advice is more than appreciated. Thanks.

 

[Nick M]

Is there anything obstructing the mode vent door? Does it move by hand easily with everything disconnected?

I asked because you indicated it was difficult with everything hooked up correctly.

 

[BigTree]

sorry I must have wrote everything all messed up there. Ya it moves quite freely (defaults to an upwards position) and I can hear it moving the door inside.

Thanks.

 

[Nick M]

If you can move it by the rod with your hand, then you need to think about the motor, and its power supply.

I don't know if the electrcial and climate control on your car is different.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=140

Examine this and compare it to yours. Unless you have the schematic for your wrong side steering wheel car handy. I would test output when you push the different buttons, and see if the control head is working correctly.

edit; I don't know how familiar you are with the electrcial wiring diagram. The 7MGTE system has a common ground setup, with power being switched. So it isn't likely that you have a ground problem, but a power problem. At least as far as I can tell from your description. It doesn't change modes when you push the selector. What does it do on automatic? Go full cold and hit the A/C button.

 

[CRE]

A couple questions...

The part in the second pic with the red dots... is that an armature with a plug/rod coming down off of it? That's what it looks like to me.

Next: On the plastic piece, above where the metal rod is bent down into it, it seems there is a track/groove cut into it. Is this the case?

If both of those are correct and there's an armature on the motor and a groove cut into the plastic part, I would suggest that perhaps the stepper motor is out of sync and the peg on the armature needs to be seated into the groove on the plastic part.

I could be way off, that's just all that I can tell from the pics and I'm working ENTIRELY from the pics.

EDITED: reread

 

[BigTree]

Alright. Nick. I know 100% sure the motor is working. When I press a button I can hear and see it move. I definately appreciate the advice though. I may x2 check tommorow though to make sure the motor is getting enough power.

CRE:
2nd pic lots of red dots thing --> That is the output on the motor that moves.

Big white plastic piece above the motor end. Yes it is grooved for the motor. When I first looked at it, it was disconnected, so I got it back together. The motor sort of pushes it around like you said when it moves.

I am going to go under there again tommorow with hopefully some more light.

The thing that really gets me though is the big "RH" arm doesnt move with the motor at all. Something has to be up there. I really really hope something inside is not messed.


Thanks so much guys.

 

[CRE]

Is the rod on the motor armature, perhaps, supposed to connect to both the plastic piece AND the end of the "L" shaped metal piece? When you get in there tomorrow keep that in mind. Again, it's had to tell from the pics, but givent the placements I suspect that's the case and there's probably supposed to be a clip on the armature's extension to keep it running through both the plastic part and the metal "L".

 

[BigTree]

damn your smart.

Should have some time in the next 5-6h to take a peek. Will keep you posted.

P.S CRE=FTW

 

[BigTree]

Well finally got it all lined up correctly and took off all the other panels. Everything moves as should.

That RH arm goes right through the box straight to the other side as well I discovered. Basically I am not sure why now but I have access to semi-defrost. Air still always tries to come out the face vents but when I put it on defrost about 70% of the air goes for the vents and the rest to defrost. If I block off all the vents I would say I get ~50% of what I think defrost should be on high.

Basically to remedy this problem I think I need to get that HVAC box in my hands to check out and play with.....something I have no plans of doing anytime soon. I appreciate everything though guys.

For what it is worth in pic #2 it is hooked up wrong where I previously thought it was all correct

 

[CRE]

Can you post up a pic of how it's all connected now?