2 climate control problems - related?

[kaspr]

'95 with dual zone climate control. I have 2 issues that may be separate, but I think they both started happening at the same time - starting a few weeks ago - don't know for sure, though. They may be related, may be separate.

Issue #1: blower motor sometimes does not come on at all, even though I command it to with the climate control interface. The interface seems to work fine, but the only problem is that the blower sometimes doesn't turn on. Sometimes the blower works from the start when I turn the car on. Sometimes it doesn't work at all. Sometimes it'll start working after 15 minutes of driving. There's no pattern to it. One important note is that when the blower motor is working, it works the way it should, increasing or decreasing speed depending on what is commanded and displayed on the interface (the module with buttons on it).

Issue #2: zoning does not work. No matter what level is commanded by me at the interface, it just blows out half and half between the floor and the windshield. Even if I set it to "mid", or "floor". It's not intermittent. It's always this way, ever since the problem started. What would cause this??

Could there be a common problem that causes both issues? If not, could someone walk me through diagnosis of each issue?

[TopherS]

Assuming that you have automatic dual climate control...

On the Automatic setting, there is a delay in the heater blower speed when it is cold. This is to prevent the car from blowing cold air around before the car has warmed up. Once the car warms up, it will turn up the blower speed as needed to warm up the temp inside the car. It will then go back down as the temps in the car near the desired temp setting. It will also control the flow to the different vents as needed.

But, overriding the Automatic setting (by pushing one of the other buttons for the settings (fan speed, mode, etc) will allow you to make the system manual. It should not delay. It should direct the flow to the vents as demanded by pushing the correct buttons. All should be done immediately upon demand.

My understanding is that the HVAC dash unit controls "where, when and how much" as far as air speed, directionality, temps, etc. are concerned. It would do this automatically on the Automatic setting, or as demanded by overriding the Automatic setting. My guess is that it is a fault in the unit itself and would try a replacement unit from a breakers yard.

[kaspr]

The climate control interface (with the buttons and display) is acting normally. When the fan is commanded to kick on, either automatically or manually, sometimes the fan does not respond at all, even though the display shows that I've commanded the fan to blow. Sometimes it works fine, sometimes the fan is dead.

Which one is most likely the problem? The interface, the HVAC programmer (computer), or the blower motor?

And what could be causing the problem with not being able to control the level (mid, floor, etc.)?

[imidazol97]

[quote=kaspr;6848286]
Which one is most likely the problem? The interface, the HVAC programmer (computer), or the blower motor?
QUOTE]

It could be the blower motor that's on the firewall behind the engine or it could be the blower control module which is in the heater box above the blower motor--it's where the wires from the blower motor lead.

Sometimes the module gives symptoms of odd speeds when it is working.

You can test the blower motor by directly connecting it to the battery with a fuse in the power lead and making sure it's got a ground.

Your air direction sounds like it is not getting vacuum. You can try putting the setting on defrost and see if any less air comes out the floor. But I suspect you have no vacuum and that's what the defrost setting is.

Check the vacuum line that runs from the motor to the vacuum reservoir on the firewall. I believe your model has the vacuum reservoir there.

[kaspr]

FYI - it was a bad blower motor causing the intermittent blower (actually it was that the electrical plug on the blower motor was loose and so the whole assembly needed to be replaced.

For the leveling issue, it was simply a vacuum hose that had come off.

Thanks for your help!