84 Bird, cannot figure out where the vacuum line goes into hvac. This car is a mess... Any help on that would be appreciated on where the vacuum for hvac enters the interior. Thought I figured it out with a vacuum line that runs next to the fuse box - so I followed the vac line into the interior... It goes back past the drivers door, then up into the middle of the t-top. I can not tell what it's function is. This appears to be a factory vac line. Any help on these two issues would be very much appreciated. Best regards, byron

 

HVAC vac comes in with the wiring; right below the heater core nipples. It's a thin plastic tube at that point, maybe 1/8" or 3/16" ID at the largest.

Sounds like you found a drain line.

 

Sofakingdom, thank you for your response. There is a hard plastic line that sticks out of the wiring in the area of the nipple. It is connected to a purple hard line that was cut off somewhere by the heater switch in the console. This hard line in the engine area has a connection that looks like it connected to either a water line/vacuum. The line sticks out of the wiring harness area probably 20" or so towards the front of the car.

Is there a way to get vacuum to the hvac without going into the dash area by the nipple? And what a strange way for a drain hole from the t-top. I will have to look further at it as it was not connected to anything. Thanks, anymore comments are appreciated. Byron

 

Why? What's wrong with the one that's there?

 

Sofakingdom, I believe it was a victim of prior owners cut and remove any wire that didn't move. I have not been able to locate, even when the motor was out... Hence the thought of introducing the vac line somewhere else. B

 

 

Well, if the old one is just gone, wouldn't be too hard to poke a new hard plastic one through that harness right there where it's supposed to go.

 

^^^^AGREE

 

Thanks guys - I have attached pictures of what I have. I thought the hard line (pic 1) was/is for the water valve (long gone). This hard line connects to a purple hard plastic line that goes into the area by the console. It is not hooked to anything. If this is the vacuum line for the hvac, what does it connect to once it goes into the cab/interior? (pic2) is a picture of where the hard line goes into the cab/interior. I have fought this car every day for the last 4 months (retired)... I appreciate your help with this.
byron

 

But your Heater Control Valve is long gone I see. It controls flow of water through the Heater Core. The first image should help ya out.

 

Bob88gta, in this forum, I found a picture that shows the hard line going to a check valve by the brake booster. I also think that the hard line tunes to a purple line. This appears it should be connected to the back of the switch. I can not find any other vac line going into the hvac system. My thoughts are, that vacuum goes to switch, switch being changed toggles between heat, vent, defrost, etc. I ordered an in-expensive 12 volt vacuum pump. It should be here in a few days. I should be able to verify vacuum leaks as well as operation - in the meantime, I have plenty to do on this beast. I just figured this out (hopefully) and came into report my findings when I saw your post. A sincere to all that responded. I will post after I get the vacuum pump hooked up. Thank you b

 

Bob88GTA, ok, got it figured out - will attach pictures of what I found. The hard plastic line goes to the brake booster area where it connects to the "vacuum ball" under the drivers front fender. I purchased a small 12v vacuum pump that pulls enough vacuum to allow the hvac doors to open when switched from ac/heat/defrost, etc. this allowed me to determine if I had a leak, and be able to hear the changing of "doors". I was concerned that with the motor running I would not be able to hear the doors moving, or to be able to determine if there was a leak or not. I had just had the dash out - then reinstalled, I was not interested in having to remove to "find" a leak. In any event, one of the pictures is the little 12 pump, another is the vacuum it pulled when connected (18-20hg) - another is the little purple vacuum line that goes to the back of the ac switch/slide changer. I connected the vacuum to the hard line inside the engine bay, then connected the gauge to the purple line inside the console/dash area. I lost a little bit of vacuum (17 vs 18 hg). I connected the purple line to the middle of the switch (picture) - the doors did not budge... my wife was assisting me (she can hear, I cannot very well). My bride suggested that I hook the vacuum to the top left orfice on the back of the switch.... immediately you could hear the doors on the hvac close - with a thud. We ran the slider switch through all of the positions, they all changed... success. I also was able to see another Bird that was an 83 - there was only 1 line going to the hvac - which was the same as this one. I would like to thank you for your help. Hopefully, someone with a prior to 86 can use this info to their advantage.......... best regards, byron