Be gentle, this is my first post (AFAIK) here.

I've got an '82 that is otherwise pretty painless to own. (Hey, I've spent years of pain getting here.)

I replaced the heater core last year and in so doing, I think I may have fouled up the works for the defroster controls.

I'm not sure if I have the vacuum lines hooked up correctly and the service and assembly manuals aren't a "great" help. I may be lazy or stupid too.

Has ANYONE ever had the problem where you move the lever to defrost and nothing comes out of the top vent? When I move it to "vent" air blows fine.

Is the defroster at all dependent upon the A/C? I think that may require a recharge because the A/C doesn't seem to work as well as it did (but that existed before I replaced the heater core) and the a/c clutch seems to cycle A LOT when I turn the A/C on (so I don't.)

Thanks much,
Jerry

Welcome to the forum!!!!
The A/C is separate from the defrost. You might have swiutched vaccum lines somewhere. I suggest you get either an AIM or a factory srvice maunal and it will help wth your repairs.
Sorry I cxan't help more but without specific routing (vaccum) quesytions, it is hard to Diagnose

I have both the Factory Service manual AND an assembly manual. I also have the Haynes and Chilton manuals for this car and the Alldata CD (somewhere.)

None of it is really good about saying, "check this vacuum line for this function." I guess what I'm looking to find out is if anyone has been through this already. I swore I hooked those things back up exactly the way I found 'em. But I've said that before and was wrong!

Thanks for the welcome! When I first joined there wasn't much here. I hope this place proves to be a valuable stop while I'm surfing.

Jerry

OK, what exactly is the problem? Air on the floor.... what?

The problem primarily seems to be an ABSENCE of air at the defroster duct. But air is definitely blowing out the front ducts. That makes me think I've got the vacuum hoses connected incorrectly.

I need to get back to basic setup for making air blow out of the defroster duct and confirm that I've got the right set up. If I knew the vacuum setting for each position on the environmental controls and which colored vacuum line it affected, it would be a good place to start. It might be something as basic as the diverter door simply sticking. In which case I'll just take a fine gauge persuader (aka hammer) to it and adjust it.

I guess I could just swap hoses until it seems to work. :p My biggest concern is that vacuum is applied in funky combinations that I won't guess.

Now that we have a long weekend, I think I'll go play with it some more and see what a vacuum gauge can persuade it into doing. I dread the task of taking the dash apart again if the hose discovery doesn't work.

Thanks for the follow up. I appreciate it.

I'm having the same problem, but I haven't done anything to the system in the car yet. Everything works except the defroster. My guess is a bad vacuum line. Post back when you can about this and any solution that you come up with.

Got an update for ya. I fixed my defroster today. I followed the vacuum line from the defroster vacuum canister and found that it was pinched closed under the heater ducting. I un-pinched it and moved it out and voila! Defroster works! Check for a pinched off vacuum line. It's tight under there and the line may have gotten pinched under something. Good luck!

I have an update too... mutliple problems were found and fixed but I'm still left with one.

The thermostat was stuck open (who knew?) which seemed to be great in the summer for preventing overheating (igonring the optimal temperature for operation, of course) but in the winter it was COLD, COLD, COLD. The gauge never moved and the heater never blew any hot air. Well, after replacing the thermostat I noticed the heater still wasn't blowing hot air. Seems the vacuum lines to the water cut off swtich were on there wrong (yours truly takes the blame... 3 nipples, 2 hoses... WTF?) So now that I have hot air and a warm car, the defroster works in the VENT mode and the VENT works in the DEFROSTER mode. WTF?!?!? I'm not sure it hasn't always been like that since my acquisition in '97 since I don't drive her much in the winter. But it does seem a bit strange that I'm left with this one confouding puzzle. I'm 99.9% sure I didn't disconnect any other vacuum lines related to the HVAC when I replaced the heater core. I double checked the hook ups at the control module with the service manual and all is color-coded approrpriately.

For now I'll live with it since everything functions properly. Just not where the selector is supposed to be.

It is refreshing to suspect a problem (stuck open thermostat) and actually find that is IS stuck open once you remove it. :-p

Pwr2Go,

Get a hand vacuum pump and check each of the four lines coming from the hvac controls. Each one routes to a different flap. It sounds like you have two of them reversed. Mark each hose w/ a number, and index the vacuum fitting on the hvac control and voila! Problem solved! Mine are color coded, but I can't remember now which was which. If I get a chance I'll pull one of the side covers off and see what I find out. Mine's a 77, so they're probably different, but maybe not.

Well I finally got this all ironed out. . .

The A/C was low on freon (which I knew) and finally got it charged. The mechanics told me they noticed it wasn't blowing cold out of the A/C ducts but out of the defroster duct. That confirmed my suspicions.

So I took everything apart again and cycled the various settings and confirmed that the diverters were acting "backwards" or opposite of what I intended. The BLUE-stripe vacuum hose goes to the left side vacuum diverter thingy and the tan one goes to the diverter control BEHIND the air box. They were backwards. The good news is that I can now take my dash and environmental controls apart in under about an hour.


Thanks for all the suggestions and not bashing my knuckleheadedness (is that a word?)

Jerry