HVAC Issues

[boomer3]

Hi guys,  when I first got my Z the heater controls were not working so I pulled the dash off and got to work. Basically the vac lines just needed to be replace/re-run. Some were rotting out, some had been taken out all together. I got the heat working, but it is now intermittent. Sometimes I turn on heat and it works perfectly, sometimes it will not come on for period of time and then randomly start blowing heat, sometimes it doesn't work at all.

 

When I move the dial to heat, and to defrost or bi-level for example, it will blow as though still on vent when malfunctioning, and then I presume the flap move to correct position when it "chooses" to start working. I'm a little baffled about what factors would cause it to be sporadic. Could it be the little solenoids under the hood, or is it related to the valve under the driver side of the dash?

[Phantom]

There is an air director gate that is vacuum powered. When you move the lever to heat, bilevel, defrost, etc. the vacuum valve is supposed to move flappers to direct the air the way you have selected.

First question - do you still have the vacuum accumulator bottle under the hood? If not, get one and get it installed. That will help with your problem. Secondly, go back under the hood and check out your air flow box and WD-40 to clean and then lube it wherever you can.

Once all that is done cycle it about 100 times from spot to spot and get it used to working.

[boomer3]

I'm not sure I understand which component you are talking about when you refer to air flow box under the hood. My accumulator is hooked up and I think is working quite well, I may try doing a little pressure test on the system some time with my vacuum tester.

 

If you can explain what/where the air flow box is, that would be pretty helpful.