So I'm having problems with the defrost on my swaped GL, from what I can find in my searching the defrost is vac controlled and to check the vac canister under the hood. I've checked the lines and have the canister hooked up and vacuum getting to the lines under the dash but the defrost still wont work.

So dose anyone know were the door that controls the defrost is at or were the diaphragm that moves it is at I'm guessing thats were my problem is at.

But what I don't get is why the defrost is the only part not working in any other car I've driven if something fails in the HVAC system it will default to only defrost for safety. But on the GL it all just comes out the main vents seems like a crapy design to me.

drivers foot well, right side. you will see some white plastic gears,

press your hvac buttons and make sure they move if they do press the defrost.

which should turn the gears to almost the end of their teeth.

i had this problem on my car, turned one of the gears and havent had a problem since/

 

i hope you can understand me, its late and i'm feeling under the weather..

The switch in the dash is what actually redirects the vacuum to the different doors in the HVAC system. I don't think I ever owned an EA82 where all the functions worked correctly. On my last wagon, I ripped the whole thing out, replaced it with an on-off switch, and connected the vacuum lines so that it was always in heat/def.

If you had your dash out for the EJ swap, check the "manifold" junction, where the line connects to the HVAC system.

 

It's just to right of where the drivers right foot would be, kinda on the side of the whole HVAC box.

The vac line coming off the motor, where's the line attached to? It needs to be on a manifold tap, not switched nor before/at the throttle body.

The vacuum pump that generates the suction that operates the defrost duct gates, is in the dashboard switch. The engine vacuum system is completely different.

theres a inline one way check valve on the vacume curcit is it there ? could it be backwards ? do you have vacume at the heater box controler?

The vacuum pump that generates the suction that operates the defrost duct gates, is in the dashboard switch. The engine vacuum system is completely different.

Nope, the switch is fed vaccum from the pastic cannister on the firewall in the engine bay side which is fed vacuum from the intake manifold of the engine. There is no vaccum pump, except on cruise control models and that's only for the cruise control.

So I finally got a chance to get the GL in the garage and take a look at it, and after pulling out the HVAC switches and finding the solenoid for the defrost door I found out I still had the vac line for the cruse control solenoid (that I removed) hooked up to the vac system so I had a big vac leak. I also didn't have the check valve in at the canister, so after getting all that sorted out the defrost works.

Thanks for all the help on what and were to look at so I could get this fixed. oh and this car did have the vac motor and I had removed it back when I did the swap so I think it was just for cruse control.