Ok, so i have an auto climate control unit, i know they suck, but it's what i got so. The air comes out every where except when you put it on heat. the heat only works when you put it on defrost except there is no heat its outside temp. So what im going to do is try to replace the vaccum lines to see if thats the problem and i was wondering if you guys new any tips to make it easier, or new how to do it without have to take the whole dash apart. Thanks for the help, appreciate it.

 

to make it easier to follow the lines it is best to take the dash out. its really not as hard as it sounds, its like 8 bolts and some wire once you get the superficial stuff out of the way (radio and lower panels, steering wheel). then follow all the vaccum lines and also check the little fan in the dash while its out. it will prolly take a few days of testing and screwing around to get it

 

What you're looking to get vacuum too for heat is the Power Servo. It's a vacuum diaphram on the drivers side closest to the firewall that controls part of the defrost clamp and the air door. Pulling the dash is the absolute best way to get a good look at it and it's not hard to do. Your in-coming vacuum line goes through the firewall into a vacuum splitter. There's a crap load of lines coming off this splitter, but the one you're looking for will go to a vacuum lock valve. It'll have one input that opens the lock and then a line that runs from the transducer to the vacuum switch behind the control unit. It's single vacuum switch instead of the multi switch that controls the rest of the vacuum servos. This switch will have two or three lines on it. I can't remember if it's two input or one, but I think it's two input lines and one output to the power servo. Commonly the problem isn't the lines it's the transducer. It's suppose to create a strong vacuum and adjust according to inputs from the ambient air temp sensor, program switch and the resistance of the temp control on the control panel. Unfortunately it has a tendency to die and you can't get a replacement. Most fo the parts in the Auto Temp system are no longer available. Hence the switch to manual control. More generic parts and easier to find.

 

Yeppers. Here's some other recent threads on auto control probs... Good reads.

https://www.zdriver.com/forums/280zx-s130-forums-77/damn-heater-21429/

https://www.zdriver.com/forums/280zx-s130-forums-77/heater-only-works-defrost-21226/

https://www.zdriver.com/forums/280zx-s130-forums-77/heater-control-switch-21096/

 

Alright, thanks you guys