legacycentral bbs

I had a similar problem with my girlfriend's Ford Taurus. It would blow cold air until the motor was very warm, like on the freeway or after an hour of city driving. We eventually found that the A/C compressor was constantly on due to a malfuntion or short circuit somewhere. If we unplugged the A/C compressor wires then the problem went away and we would get heat sooner.

You might want to check this as well, if you are getting what feels like A/C air when you have the temp control slider anywhere but on full heat and you are getting noticeably cold air even with the A/C button off.

Oh, and i would avoid pulling your heater core unless you do find that it is clogged or leaking. Mine was leaking and installing a new one does require pulling the dash as well as the A/C system's condenser unit. The condenser unit's plastic housing sits on top of the plastic housing for the heater core so you have to pull the A/C side first to get to the heater core, which sucks because you have to let the freon out of the A/C system to do this. I still haven't had my A/C recharged after this repair. I will have to soon though because it gets really freaking hot in the Redding CA area, like 115. Really really hot.

the a/c core doesn't sit on top of the heater core for the subarus. It's before the heater core.

You still have to pull the dash....but you shouldn't have to discharge the a/c system.

nope, to remove the heater core you need to discharge the a/c system

Josh,

Its been almost two years since I posted on this topic and thought it was the actuator motor so I got a new one and installed it. It worked for about a minute then the buttons didn't work again! So obviously it had to be something else and then I found your post on the HVAC control unit with the cracked cold solder joints. I took that out and looked real closely under a magnifying glass and at first didn't see what I thought were cracks but as I looked again more closely, I could see small indents in the solder joints. I found six joints that could have been the problem and went ahead and resoldered them all just as insurance. Slapped it all back together and I am back in business! All buttons work flawlessly and I could switch back and forth to all of them with no problems at all.

Thanks Josh for sharing this info. It really helped immensely!

Welcome Glen.

I know it drove me nuts when I was having that problem.

My 93 had a similar problem with the hvac too. I couldn't change where the heat/ac went. I did the "piano" method and it seemed to free up for me. But when it was in the off position, I'd hear a wierd sound, like a steady "tip tip tip tip" sound coming from the dash. It happened only once in a while. I'd just turn it on vent and it would go away. My 94 hasn't has that problem yet (knock on wood).

Richard wrote:My 93 had a similar problem with the hvac too. I couldn't change where the heat/ac went. I did the "piano" method and it seemed to free up for me. But when it was in the off position, I'd hear a wierd sound, like a steady "tip tip tip tip" sound coming from the dash. It happened only once in a while. I'd just turn it on vent and it would go away. My 94 hasn't has that problem yet (knock on wood).

I have a similar problem, today i was looking for about one hour, and i found that the problem was the actuator motor, because the levers in one position doesn't work as free as i think they have to work, so the motor is working in a "hard condition". Tomorrow i will try to lubricate the levers and see what hapen.

.............very difficult for me to explain in english. I have to practice with someone bye MSN.

uhhhh...

I just noticed this thread...( I must be retarded)...but in a similar situation to what subylvr was posting about I do lose heat unless the engine is actually doing something. For instance when I am driving I have fantastic heat....but if I stop .. leaving the engine on and....say...wait to pick somebody up, the car will start blowing colder...(not freezing) air. Now, if I really wait there and its really cold outside the car will actually cool down (temp gauge) from its normal state of just below half way, and the air will get really cold. Is it abnormal to not have heat at idle? (this question goes out to the folks who actually know what winter is and have experience in below zero temperatures (and were not in a walk in freezer))

Umm. Yes. It is abnormal for you to start getting cold air if the selector is on warm and you have the heat on and the engine is at normal operating temperature.

Do you have a subaru OEM thermostat?

It sounds like that could be the problem

Im gonna go out on a limb and say no. After checking through some old records from the previous owner I noticed there was a thermostat but nothing that indicated it was OEM. Is it expensive?

Oh and since you came back to this thread josh is your HVAC still working perfectly since you resoldered those connections? Mine does the same flipping thing with not switching to the desired location.. it could take hours or days to switch.



(if you havn't noticed by now I am one of those members that reads these forums all the time but rarely ever posts)

The thermostat was $10 from www.subarugenuineparts.com It may be a little more from a local dealer, but shouldn't be too much more.

Regarding my HVAC controls. They've been working 100% correctly since soldering the pins.

If the HVAC isn't working properly, yet there are no obviously visible defects in the solder joints, would you just hit all the joints (where the cable hinges between the two boards) briefly with the iron or start looking for other things that could be the culprit?
When I say the HVAC isn't working properly, it's the similar problem with the vents not switching between floor and dash, as well as the AC not blowing cold except briefly when it's switched to bi-level or after a particular Maple Street speed bump.

The ac not working sounds like a temperature switch issue.

I believe I hit all the pins in that area where the solder had shown signs of cracking.

This is what my car does, I'm copying and pasting from USMB lol, I think part of my problem is the heater controls but the fan also works intermittently...


My 1990 legacy wagon has issues with the heater controls, there is a constant squeak squeak squeak from under the dash, sometimes goes away when you shut the ventilation system off. Also, the heater/AC controls dont' always work, the air doesn't like to come out of where you have it set (when I first got it, air blew out the defroster vents regardless of where you had the controls set, then after a while it would switch) and the blower fan works when it wants to. For example, tonight I was trying to charge the AC and I'd hit the "A/C" button and the light would come on, but the compressor wouldn't engage, and if I started pushing buttons I got the AC to kick on and the fan to come on, but it's really annoying like in the morning when I'm driving to work and freezing my arse off because the only air flow I'm getting is the natural flow through the car, same deal on the way home when its 90+ out and I've got the windows down and the sunroof open because the fan won't work... but it's intermittent so I'm not too sure where to start, I suspect that the control unit is bad but I don't know how to test it.

Also, if it is bad, is it possible to swap in the electronic climate control?

Sounds like the control unit is toast. You'd have to get all the sensors to swap in electronic climate control. I don't think it'd be worth doing that, especially if you have to wire everything.

well, 263,000 miles it's probably time to get a new(er) unit What sorta sensors does the electronic unit have? Wiring's no issue for me, you have a diagram? If it's a super PITA (probably a PITA to find an electronic control unit, since I have yet to encounter one) I won't bother lol just thought it'd be cool.

The electronic unit only came on the 90 & 91 LSi's I believe. I might have some diagrams but I know it wouldn't be fun trying to put the sensors in....let alone trying to find an electronic unit.

Okay, so I took the unit out and found one cracked joint and one questionable one, both of which got re-soldered. Now the controls work perfectly, but the fan does not work AT ALL. This morning on the way to work it came on for about 15 minutes then puked again, and this afternoon on my way home from work, it didn't work at all no matter how much I futzed with the unit. I know the fan can't possibly be directly controlled through the hvac control unit since the wires going to it are way too small, plus the fan switch isn't really part of the electronic part, it's just attached to the same face plate, however it must be controlled through a relay of some sort since pressing the OFF button on the control unit will shut off the fan (at least that's what it's supposed to do, however in my case it stays off...) The fan has been intermittent as long as I've had the car, so I imagine that relay finally gave up the ghost, however I have no idea where it is or how to test it lol.....

You can find relay location info on my site
http://www.surrealmirage.com/subaru/swa ... html#relay

MAn am I glad that the relay wasn't the problem, that sucker is BURIED lol, the problem was still the stupid connector on the back of the unit, took it apart and soldered the $%*$* out of it and it works now The lights don't work, which kinda sux at night, so I think I'm gonna open it up yet again and test the lights and see if they are burned out, or if I have a bad connection, since one light used to work and now they're both dead, I'm suspecting a burnt out bulb, but we'll see.

+1 for bad soldier problem.

I took a close look and redid several pins, works like a charm now. The cracks can be small and hard to see, but you're right, they're there.

I had the exact same problem with the solder joints. Once I got everything soldered I tested it several times in the car and everything worked perfectly. So I got to work on putting everything back together. Once everything was buttoned up I started it up and started to pull away from the house, hit the a/c button and NOTHING. I had back up the 6 feet that I had gone and got to take everything apart again. Turns out, after I had tested it, I crammed everything back into the dash and that had pinched the cable enough to torque that plug again enough that none of the buttons worked at all. So after that got fixed and everything put back together on the dash, the a/c works fantastically. Thanks for all of the write ups on this issue and everyones help.

HondaSucks.
the "lights" are LEDs and if all of them are not working then there are other issues with your HVAC control head. LEDs don't natively operate via 12vdc so there is probably some sort of voltage regulator integrated into the back of the control head. another assumption that can be made is that if the control head switches are getting system voltage from the car to excite the A/C control relays, then the LEDs VR should also. The VR might be fubar. test with a multi meter with 12v to the appropriate pin on the back of the control head plug (maybe just plug it into the car when it is disassembled), probe one side or the other of the LEDs for 3-5vdc. If it is not there then the VR is toast, or has a bad trace from the intermediate plug board.

Hope this helps. My 91 L wagon had this issue (no work buttons-A/C) not the "no light" problem. After the resolder of the intermidiate boards interface plug all was well (also after a A/C recharge). This thread is what turned me on to the problem.