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Discussion Starter #1 (Edited)
* Pictures will be posted and updated later *

This has been coming up a lot lately, the original thread is here with no pictures and ridiculous detail, scroll down for the write-up:
http://www.preludeonline.com/showthread.php?s=&threadid=103800

SYMPTOMS:
When your driving your car at night and hit a bump, all of a sudden there are no lights on the climate control in the center of your dash .. then they will be there and flicker and go on and off ... Or, the lights just dont work or go on / off when you hit your dash (mechanical tap).

When your changing between the vents to the upper Vents, Floor/Vents, Floor and sometimes the airflow will change and sometimes it wont. The buttoms may or may not light up to the selected airflow. If you let it sit there, it will eventually go where you want it ... sometimes not.

A/C doesn't work. The green light may/may not come on with the button being depressed. A/C will work sometimes, but other times it will blow hot air or go warm/cold and cycle between sporadic.

CAUSE:
Where the wiring harness/plugs go into the underside of the climate control, the solders on the pins that go into the plug come loose and dont make a good enough connection to the airmix unit (on the firewall behind center console).

THE FIX - IN A NUTSHELL:
In a nutshell, take out your CC, remove the casing, pull out the circuit board and re-solder the backside where the pinouts go for the plug. To define resolder: Heatup the solder on every pin until it melts and cools. Add more where needed. Let it cool and put it back .. voila!


THE FIX - DETAIL DETAIL DETAIL:
First things first, and the 2nd most pain to do of this repair:

Take off the shift boot!
Get a cloth and put it over a flat head screwdriver so you dont damage the shiney plastic covering on your shift knob. Above the shiney ring, insert the screw driver and pry down (Insert it from the back side facing the trunk of the car. When it comes down a little bit, hold it down and replant the screwdriver lower so you can pry it down furhter and further, eventually it should just pop off. The first time I did this I was able to hold ALL of my body weight on just the top of the boot and it came down.
* Other info - you can't see this when the boot is on, but there are 2 plastic tabs that the plastic part in the boot clip up onto, they are towards the front/rear of the car on the shift knob, thats why you want to pry from the back/front of the knob. You'll see what I mean when its off.

Unscrew (counter clockwise) the shift knob.


Take apart the Center Console
- Take off your stereo faceplate and remove everything from your ashtry and storage compartment (if you have one).

Put the driver & passenger seats all the way back, on either side of the Center Console there are a series of screws - take them all out. Dont mix these up and make sure the metal clips on the inside stay there, they allow you to screw this back on tight. Underneath the climate control (above the radio) are 2 more screws, take these out.. You should notice the center console is loose now .. so lift it up on the sides where its split and pull it off, put this aside somewhere that you wont kick it or scrape it on the ground. Remember, the LED for your alarm will be connected by wires, dont pull the light out or you'll need to glue it back. Dont forget to hook this up again when you put it back together.

Now your staring at your stereo, Remove the 4 screws holding in this part and remove the stereo holder. Remove the harness' behind it and antenna etc. before pulling this out. Now you should be looking at an empty dash, a bare shifter and the climate control begging to be removed.

Everything up to this point should be familiar if you've installed an aftermarket stereo and/or speaker wiring to the tweaters. Time for the goods:

Remove the Heater Control Unit

Before removing this you need to know: The vents AND climate control come out as ONE unit. You will remove the vents after.

3 screws hold this in, on the left of the CC, and on the right of the CC up underneath where the 2 screws are above the radio and on the outside, take these out. You'll notice the CC is now loose, time to have fun. Make sure all of your car parts are out of reach of you feet. I scraped the piece under my glove box on the concrete by kicking it by accident (doh!) This gets tricky.

Unplug the climate control, theres 2 plugs. One is brown (fan speed) the other is green (everything else). You'll notice 2 screws up under there also, one is for the temperature cable the other is holding in the climate control. Remove it and the climate control will slide forward *BUT* not come out yet.
I think the screw was originally gold, but I lost it and replaced it with a black one.


Now its time for the screw holding the cable, this is attached to a little bracket that screws down and has a lip on the end of it holding the cable secure. This is impotant t not to mess up and I'll explain later why. Unscrew it enough to get the cable loose, then tighten it again so you dont loose it. You need to manouver the CC unit out of its holding area where you'll see a longer piece of metal held down, there is a plastic slider that is looped on the inner cable that changes the temperature


You want to unscrew this just enough to manouver the hoop on the end of the cable off of the plastic slider (you'll be prying the plastic slider up to get the loop off) and when you do .. voila, you dash now looks like this :


Now unclip the vents (they are held in by 2 screws also) and you should have this for your CC...pull off the front buttons, carful with the clips they will break very easily! I dont know how to avoid snapping them..



and then the circuit board slides right out. There is one light bulb that is connected to a thin cable (dont have a pic, sorry) make sure you dont rip this off.. As mentioned below, this is the area of concern:



These are the loose solder connects (the ones on the reverse of the green plug). Heatup your soldering iron and touch all of these solder points, melt them ALL , the reason I say all is because I cheaped out and did most of them .. now my AC isn't always working .. but everything else, including lights does.

Put the buttons back on the front, take it to your car (just the bare circuit board) and plug it in, with the key turned all the way forward (and car not started) you should be able to change the vents and listen to hear it change now ALL THE TIME :eek: .. hurray! your done! .. If you have lights in the CC you'll notice that they are turning on also .. bonus!

Now reverse the steps and put it back together. You may need to spend some time adjusting the slider cable so that it goes all the way to cold and all the way to hot without having a gap in between, pretty straight forward just tighten the clip on the cable in the grooves that are there.


Submit pics here: http://www.imagestation.com/album/?id=4286097461
 

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Premium Member
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383 Posts
You are a freakin GENIUS!!! I just fixed mine. I took the whole thing apart and checked the soder points. they were SO bad it isn't even funny!! This looked eqactly like my 4WS ECU issue.

Two of the connections were so bad I couldn't believe it. There was a hole in on of the points.

I reinstalled everything and tested it out. Works PERFECTLY. I wonder if this will fix my AC issue too. I hope it does.

Thanks for the help!!! I have been able to fix my 4WS issue and now this because of you guys! Great job!!!
 

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Third time is a charm.
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1,144 Posts
wowsers this is very helpful!!!! thanks a lot, too bad it wasnt done while i was tearing my dash apart haha
 

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Buttering up the muffin
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965 Posts
Area of Concern:


Resolder these 16 pins - you really don't need to if it's just the A/C not working - but the other pins also had solder cracking.


If all else fails, resolder the switch. It's the 2x3(6 pins) closest to the black LED housing. If the LED does not turn on, try resoldering the 2 pins directly under the black LED housing


Test Your Switches:
If you have a multimeter handy, test the continuity of the pinouts. If the meter beeps steadily, your fine. If it's on and off, resolder the appropriate pins.

A/C pinout


Mode and Reciculation pinout


Rear Defroster pinout
 

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236 Posts
i took everything apart, the filiments in the bulbs are intact completely and the solders are all mint everything was clean.. its a 93 so it has age but i couldnt find anything wrong =\ i cleaned stuff up a little and ill put it back.. i guess i will check the harness to be sure thats not dirty
 

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Premium Member
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2,208 Posts
Discussion Starter #14
did you not solder those connections? mine lookd fine when i did it and I still resolderd and it fixed it.. i didnt touch all pins, now my ac doesnt work all the time.. im gonna do it aagain and have more photos
 
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