dlagerstrom

So, the last item on my list is the HVAC. Car is '82 US 5 speed. Symptom is center vent not working. All vacuum is tested and working (can open center vent with mity-vac, both positions)

I tested the mixing motor according to the WSM. It has you test certain points on the connection and some need to be at battery voltage and some ground. WSM 87-113 titled 'Testing Setting Motor.' The motor itself works (moves as I move the temp slider) but test 7 fails. Terminal 8 on plug one should be battery voltage but I have nothing. Terminal 8 is connected to the center vent. The WSM doesn't say what to do if a test fails.

I am thinking I need to pull the mixing motor and open it up to see if anything looks out of place. Any other thoughts?

Thanks for your support.

dr bob

For sure the motor and the little gears and switches need to be cleaned and gears lubricated. That may be enough to restore the center vent function for you.

dlagerstrom

Thanks Dr. Bob.

I pulled the motor and dug into it. Really nothing in there to go wrong as far as the center vent issue. I am guessing my issue is someplace else.

Great idea to clean and lube while I am there. Will do.

The Forgotten On

I recently readjusted mine by the WSM back into spec and it got the recirculation flap to work along with the full open on the center vent flap.

I also recommend cleaning the contacts after taking it apart and servicing it as recommended above.

dr bob

^^^

What Blake said, particularly about cleaning the contacts. Getting the center vent operating correctly is key to effective AC; If the vent isn't right, you'll see no lower than maybe 50ºF AC vent temps.

The Forgotten On

Adjusting it allows it to reach the limits inside of the motor and make connection with the correct contacts.

It's one of a few things I wish I did while I had the dash out. Good thing we all become contortionists when getting under the dash

dlagerstrom

Thanks everyone. I really love this place.

I am sure you have nailed this one. When I had the box out, I replaced the foam insulation on the flaps with what I had. It is a little thick and stiff so I am sure the flaps are not closing as before. The motor was about 1mm away from bottom when I pulled it out. Will update after testing, hopefully lengthening the rod a bit will get me back and I don't have to pull the box apart again.

Shawn Stanford

My center vent was working fine when I pulled the dash apart, but it's not opening now. I think we're talking about Flap 'E', the bulkhead flap. Is that correct?

Whitesands

Also check the micro switch in the center vent, mine had sized telling the system that the vent was permanently closed.

dlagerstrom

Shawn, yes, flap E is the one I have been talking about. As I can tell, if the flap is not opening the system has an error and believes heat is required. The error can come from a number of places.

What have you tested?

Shawn Stanford

I actually haven't tested anything. I only noticed the problem a couple days ago when I started driving it again. I don't have the dash and console completely reinstalled, so I just pushed the flap down by hand and stuck something in there to keep it open.

I took a look last night after posting the diagram and I found that some of the vacuum lines were knocked loose during the process of removing and reinstalling the dash. I reconnected the green line at the solenoid, I reconnected the orange line at the actuator, and now I have a purple line that looks like it wants to head up under the top of the dash. I'm thinking it's for the mixer flap, but the diagram says that should be a yellow line, not purple. I'll trace it back to the solenoid to make sure.

dlagerstrom

The purple vac line also connects to the center vent actuator. Our cars have a 2 stage center vent. Yellow line is for footwell, red is for mixer (comb) and heater valve. Green is defroster and blue is recirculating air valve.

The book calls out the purple one as brown. Maybe Germans are color blind?

Shawn Stanford

Okay, so Orange and Purple both go to the center vent actuator. That being the case, which line goes to which connector? I see a low and a middle in this pic I found in another thread.

dlagerstrom

In the photo, upper unit, orange connects to the pink section, purple to the black.

Shawn Stanford

Awesome! I'm going to reconnect them as soon as I get home tonight.