HVAC controls not working all the time

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Legacy777
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HVAC controls not working all the time

Post by Legacy777 » Sun May 18, 2003 10:07 pm

Some times when I push the button to select a different HVAC setting, ie vent, a/c, etc. it doesn't do anything.

It has been intermittant so far, but I can only assume it will get worse.

I haven't really looked at the manuals yet. I figure it's either an electrical issue or something may be tits up with the vacuum actuator.....if that's what we have....

Anyone have any experience with issue like this?

Thanks
Last edited by Legacy777 on Fri Sep 10, 2004 4:08 am, edited 1 time in total.
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Post by DerFahrer » Sat Jun 07, 2003 3:07 am

Actually, I'm having a weird HVAC problem myself. Keep in mind that when the "Off" button is pressed, the compressor is not on, the fan is not blowing, but the vent is circulating air down at your feet when the car is moving.

Occasionally, when I push a button, A/C, Max A/C, Vent, doesn't matter, any one that is supposed to direct air through the dash vents, it won't. It will continue directing air towards the feet, and no air through the dash vents. I usually notice only when my feet are freezing and my torso is burning up :roll:. To fix it, I simply take my finger and run it across every HVAC button there is, all the way across, like a piano. About 3 seconds later the foot vent closes and the dash vents open.

I have no clue, and it's hasn't done it for awhile...
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Post by Legacy777 » Sat Jun 07, 2003 4:09 am

this is exactly what mine is doing.

i did some more snooping and found someone else that had same problem, and said it's an issue with the conector in the back of the unit. I may try and reach my hand up there and wiggle the connector to make the connectors better.
Josh

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Post by LegacyLuvr » Mon Jun 09, 2003 10:19 am

Same problem for me too. So I dug out the service manual and found out that its a motor driven vent door that is sticking. I did a temporary fix that has worked great for me. First, start your car and push the A/C button in. Then, under the console behind the stereo on the drivers side is the heater unit. You gotta kindof crawl up in there. Look up and you will see the side of the heater unit. On the side of that, you will see a 3-4 inch thin metal rod called the rod-motor actuator. It is attached to a metal plate that has two legs on the bottom of it. Grab ahold of the actuator rod and push it towards the firewall. That should free the motor to move the Main link plate forward and open up the vents to your dashboard. If it doesn't free up at first, just give it a few more tugs.. If you are still not getting anywhere, then its possible that the motor is not working. The motor is a small cylindrical unit just to the right of the actuator rod. This has solved my problem of playing the buttons like a piano too and to keep this working, I never push the OFF button. Before I get out of the car, I just switch the A/C button to VENT. This will keep the vents open. I can switch to MAX A/C to A/C to VENT back and forth with no problem. If you switch to OFF, the actuator motor will engage and close all the upper vents which will send you back under that dash to start all over again.. I just did this for now until I get the time to get in there and do the real fix on it but for now, the A/C is pure bliss again! :D
Glen

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Post by Legacy777 » Tue Jun 10, 2003 2:03 pm

I'll have to take a look at this motor/rod setup to see if I can figure something out.

Maybe lubing the track guide or something.
Josh

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Post by LegacyLuvr » Tue Jun 10, 2003 10:43 pm

Yea, I think its just something that needs cleaning.. I did the pushing several buttons routine to get it to work for awhile and finally it just wouldn't do the trick anymore. So I had to dig deeper. Its probably something that needs a little cleaning and lube. Hopefully a 10 minute fix.
Glen

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Post by Legacy777 » Sun Oct 26, 2003 9:57 pm

Well I got around to pulling the dash apart to get after the hvac controls. I couldn't get the black trim off without removing the steering wheel. So I had to wiggle around the black trim.

What I did was remove the connector for the HVAC controls, (not the fan control one) I cleaned both sides out with electronic cleaner, and then blew air to dry it. I then put di-electric grease in there as well. I did this because it acted up a lot more when I ran the A/C so I think there was a moisture issue. I also put a little plastic piece under the connector to help put some pressure on the connector to keep the contacts in touch.

Everything seems to be working well. Hopefully I'll know in the next couple days whether this has fixed it for good or not.
Josh

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Post by Legacy777 » Sun Nov 02, 2003 8:34 pm

just to update......buttons have been working great, no issues. Not sure whether it was the cleaning of the contacts or shimming.
Josh

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Post by Legacy777 » Fri Sep 10, 2004 4:08 am

Ok....time for an update to the update. The buttons have been cranky lately. So I got fed up and pulled the HVAC unit out.

The issue definitely is the pins de-soldering themselves from the main board.

The solder was cracked on three or four of the pins. So I re-soldered those pins. I didn't do all of them, because I suck at soldering and didn't need to fubar things up any more.

I put everything back together and it seems to be working beautifully.

here's some pictures of the hvac unit, connector, pins, and dash.
http://www.main.experiencetherave.com:8 ... ages/hvac/
Josh

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Post by DerFahrer » Wed Dec 15, 2004 5:14 am

I've been having this problem very often lately, it's about time I did this procedure.

It did something new tonight though. It got a bit nippy here (hey! we consider 40 degrees cold :lol: ), and after the car warmed up, I turned the heat on, using the Bilevel button. It blew nothing but the cold air that was outside. I turned the temperature all the way up and the fan all the way up and it was freezing cold. I turned it off. Tried it again a couple minutes later, and bam! there was heat. It started cooking me alive in a matter of minutes like it usually does...

Just a glitch? Or is there possibly a problem with the cable or whatever that's attached to the temperature control?
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Post by Legacy777 » Wed Dec 15, 2004 4:33 pm

The temperature control is purely mechanical. The cable can move slightly. It's possible it moved a little, but you should've gotten some heat.

You might want to move the cable back and forth and check out the mount point and see if the cable is sliding. If not, maybe you had an air pocket.....I don't know.
Josh

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Post by stant093 » Fri Dec 17, 2004 5:29 am

I had the same problem awhile back....evcentually the buttons just stuck...eventually all the buttons were pushed in.... :cry:

I ended up fiinding a parts car in the junk yard ($15 and a laugh when the guy saw what i pulled) and pulled the HVAC setup out, cleaned the new one right up and plopped it in, took no more than a half hour....and if you jimmy it just right you dont have to pull the steering wheel off....pretend its a rubik's cube if ya must :)

Needless to say i have a nice functioning control panel now....

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Post by DerFahrer » Tue Jan 25, 2005 6:59 am

How's this for weird??

When I have the heat on, it blows cold air below 1500rpm. Above 1500rpm it cooks you alive like it's supposed to.

:?
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Post by Legacy777 » Wed Jan 26, 2005 5:20 am

sounds like your water pump may be on its way out, or your cooling system/heater core may be clogged/restricted.

Is the heater lever all the way to hot?
Josh

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Post by DerFahrer » Thu Jan 27, 2005 6:41 pm

My water pump is barely 20k miles old. I haven't seen anything weird happening with my temp gauge, and we all know just how accurate those are :roll:

Where should I look for a clog?

I forgot to include that when the heater lever is all the way to hot, I don't have this problem, it still blows hot even at idle. But if it's below that, then it does this.
2000 Subaru Legacy B4 RSK

"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"

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Post by Legacy777 » Fri Jan 28, 2005 1:09 am

have you checked the cable going to the heater flapper door?

Really don't know where to look for a clog. Check all the heater hoses and make sure they're not crimped or look collapsed. that'd be a good start.
Josh

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Post by DerFahrer » Wed Feb 02, 2005 6:50 am

Excuse my ignorance, would that heater flapper door have something to do with the flapper door between the feet and head vents, since I've been having bad problems with that lately, but have been too lazy to do anything about it...
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Post by Legacy777 » Thu Feb 03, 2005 3:21 am

no, that's a different flapper door.

http://www.main.experiencetherave.com:8 ... ACdiag.jpg
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Post by DerFahrer » Sun Feb 20, 2005 6:54 am

One more thing I think I should add:

If I have the heater going full-blast, I hear an audible (but not deafening) humming/moaning from the dashboard, it's actually been doing that since I've had the car.

I'm suspecting more and more that my heater core is clogged... Now everyone says that requires removal of the dash, does that mean the entire removal of the entire dash piece from the windshield back?? Or can I remove some stuff out of the center column and get to it?

Also, if my heater core is indeed clogged, how much extra stress am I putting on my cooling system? Am I causing undue stress on my radiator? hoses? new water pump??
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Post by Legacy777 » Mon Feb 21, 2005 4:41 am

The humming is probably the fan. You could take the blower motor out pretty easily to check.

You could try removing the coolant lines going to the heater core, drain them, and see how well water flows through, or blow through them. Worst case if it is plugged and you're worried. Just bypass the heater core, by connecting the input and output lines together.
Josh

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Post by DerFahrer » Tue Feb 22, 2005 5:14 am

The humming only happens when I have the heater on, not when I have the fan on...

Do I have to take the whole dash apart to get to the coolant lines on the heater core?
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Post by vrg3 » Tue Feb 22, 2005 5:22 am

If you just need to access the lines, couldn't you access them from the engine bay side?
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Post by petridish38 » Tue Feb 22, 2005 12:42 pm

vrg3 wrote:If you just need to access the lines, couldn't you access them from the engine bay side?
Yes you can. Then couldn't you try to flush the heater core out with a garden hose?

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Post by Legacy777 » Tue Feb 22, 2005 3:37 pm

Yeah....I'd try what Andrew suggested.....pull the lines out from the engine bay side and try flushing the sucker out.
Josh

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Post by DerFahrer » Tue Feb 22, 2005 6:03 pm

Very good suggestion. I will try that. Thanks guys! :)
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