shmark

Lately I've noticed something not quite right with my center vent. The symptoms are no "mix" to the air coming out - it's either full-cold or full-warm. It does cycle automatically so the temp sensor works and the passenger footwell flap is working fine, just doesn't moderate the temps coming out any more. Also there's not as much air coming out of the center vent any more. Used to be near-hurricane force and now it's probably half what it should be.

Something is stuck down in there, where should I start looking? Vacuum issue or something has come adrift, I'm guessing.

joejoe

I think the center flap on your car is operated by a microswitch. If so there are only 3 positions: full open, half, and close. (I am envisioning my '81) There is also a comb filter inside center flap. Mine broke off the plastic hinge which holds it and wedged causing poor air flow. There is a duel vacuum pot in there that works the doors. My understanding is it is no longer available.

You can carefully pull center vent to see if comb filter is problem. If you look through it even you can probably see if bad.

Going full col/hot seems to be temp sensor. Check outside sensor (driver side front flap) You need to remove flap and will see where alternator hose goes. At the end is a sensor for outside ari in a metal tube. Clean contacts, or in my case reconnect. The inside sensor is on dash and there is a small fan that may have stopped. You can easily see if working using smoke to see if fan is drawing. To remove is a bit more difficult as you need to get behind and undo nut that holds unit in place. If you try just pulling it out the plastic cap will break. Hope this helps some.

Alan

The 3 posistion console vent (comb) flap is unusual - it only apeared for a few years. '83 is one of them. I think you need to describe the situation better however... when you say full /hot of cold - does this apply to the air from other vents too?

If all the air is eather hot of cold then you have a problem with the temperatiure sensor loop - if it is just the console vent it is probably related the comb flap...

Alan

shmark

Thanks for the info. The full cold/hot comes from all vents, not just center. But it actually cycles between the two which seemed to mean that the temp sensor was ok...maybe I'm wrong. The net effect is it's keeping the interior temperature where I set it, just working with two extremes instead of a mix. That, combined with the reduction in airflow pointed to something blocking, like the comb flap. It's hard to get into the garage during the week but I will pull the vent this weekend and see what's up.

Mrmerlin

before you pull the vents try going to Wallys tip page at www.928gt.com and testing the vacuum pods by removing the left side console cover