6mil928

Been trying to get my A/C going in the 81. Got it charged up and it's still not getting very cold. I'm gonna deal with the A/C furthur but I have another question. Most of my air was coming out the defroster and the center console flapper was closed. The center console vent opens and closes randomly possibly with engine vacume but not for sure on that one. The real question I have is there is a piece of plastic with holes in it behind the center console vent flapper that appears to be hanging from one side and just banging around. If I move it say to the back it seems to shut off the air flow. I assume it's broke some how. What is this piece of plastic? Also I get no air from the vents on my door panels in what position should I be getting air from them? Also on the center console vent what should the lever to the right be doing? It clicks but appears to have no effect. If the auto system becomes a hassle can I change it to the manual HVAC system? Jason

the flyin' scotsman

I cant speak for your MY but on the S4 there's a comb that supposedly mixed the air at the centre vent and also restricts flow.

My solution was omit the comb and the respective vacuum plumbing and have max flow........poor/over design IMHO.

dr bob

There are a couple little doors in there attached to the little **** you are pointimg to. Pull the center vent assy straight towards the rear of the car and you'll see how they work. Forward of that in the duct is the comb flap, actuated by vacuum in the system when you select defrost or floor vent position. Or when the actuator fails. If it doesn't go open when you have the flow selector at the rectangle position (right next to the left/off position in my car), you have a vacuum problem someplace.

The default positions for vacuum actuators are defrost vent = open, floor vent = closed, comb flap = closed, fresh air flap = ?, heater control valve = open. Pretty much says there will be hot air blowing on the windscreen and inro your face no matter what.

Recommendation: Find and fix the vacuum problems. Heat will go off, air will go through the AC evap and into the car. Roger (ROG100) has some of the vacuum diaphragms to make the job a little less spendy, compared to buying the whole actuators. The tips pages have write-ups on the diagnoses as well as the fix methods.

joejoe

Picture on the left is the comb flap. It is attached by rivits and is poor design as the plastic hinge breaks. I have not found a good replacement hinge. Mine also broke ('81) and I removed it. It is connected to a vacume pot so you need to plug off (can be seen when consul is out), or if glove box removed (I think). The lever on the right is a 2 position micro switch. All the way up and vent is full open. Down to first click and vent closes half way. Next click down and vent closes. Mine also seems to have a mind of its' own at times. Wish it was set up like my '86.5 where lever manually opens/closes vent. Hope this helps.

6mil928

Thanks guys. Should I remove the flap like suggested? It does appear that all my settings are at the default position. Can this be fixed by pulling the side panels on the console or do I need to pull the console?

dr bob

A vacuum leak at any active actuator will cause all of them to go to default position. Find the leaky one using a Miti-Vac, each circuit one by one from the little rack of solenoid valves in the center console. I used John Pirtle's write-up and it was a good procedure.

zekgb

Make sure that you start the vacuum troubleshooting process from the brake booster forward. I chased what I thought was a leak in my recirculation flap actuator - it turns out that the vacuum line to the recirc flap was disconnected at the firewall and for some reason the previous owner thought that the open end of the 4 way vacuum splitter that's connected to the check valve could be capped using a metal screw and I guess when that didn't work out so well he just put an inline cap on the black line that provides vacuum to the cabin, which resulted in what looked to be good vacuum when testing with the MitiVac from the cabin. Long story short, I spent 4+ hours doing a 15 minute job.....

dr bob

There are possible issues with the Tee and the line from the booster to it, from the reservoir, a disconnected line anywhere in the flappy plumbing, the check valve, and then and only then the little rack of solenoids and the associated plumbing.

It's still easiest to start at the center console area since theta's where all the fun stuff comes together. First step there would be to pull the supply hose off the rubber manifold thingy there and connect that hose to the miti-vac. Don't spend time trying to draw a vacuum with the hand pump; Instead, just start the engine and observe that you have vacuum on the miti-vac gauge. If yes, get to work on testing the individual actuators. If no vacuum, work your way back to the Tee and the check valve to get things reconnected.

6mil928

That is excellent TS advice. Thanks Bob. Jason

6mil928

Is it tough to pull the center console? I've been thinking of doing it?