dprantl

Too bad. I'm not aware of any generic parallel-flow condensers that are smaller than 12"x14". Maybe scour a junkyard and look for some from small cars. You can get away with a much smaller condenser than stock if you go to multi-pass parallel-flow. These are hugely more efficient than the older serpentine/tube-fin condensers.

Dan
'91 928GT S/C 475hp/460lb.ft

Donald

Don;
Thanks, I would like to KISS (me being the second "S") and clean so cam switch sounds best, and yes to the schematic.
My goal is just to update the look, not to embark on a BrendanQuest.
What type of computer do you have?

Don Ashe

Here are some pics of the switch. (I have it apart to make a new faceplate)
The second pic shows the hex filed into cam a. A wire spring rides on this to act as detent for the six positions. The last one shows the cutaway to house the cam switch. If you don't want to hack up your case, the switches could be mounted to a separate panel and the housing mounted elsewhere.
I'll add a schematic soon.

-don

Don Ashe

oh yeah - the computer is an intel D201GLY motherboard I picked up on clearance at Fry's for $30.00. (the ram cost $40.00!) and a 500 gig notebook drive, in a homebrew case with a mini-box M3 ATX power supply. The monitor is a Lilliput 629 with the touchscreen removed - I don't like touch screens in the car.
For input I use a scroll wheel mouse - left is rewind/back right is fast fwd/next, press the wheel for pause/play and scroll up and down for volume. Clicking left and right simultaneously launches my menu app, also driven by the scroll wheel.
The OS is Arch Linux with X-Windows and MPD and my own software to drive MPD and the menu system. I don't use the wireless or browser much, but I do keep a keyboard in back, just in case.

HTH,
-don

Don Ashe

Donald-
Here is the HVAC controller section of the schematic from the 84 wiring diagram. The switch symbols actually indicate the pc board traces that are bridged by the wiper attached to the slider.
(I hope the little ascii symbols work to indicate up and down and the rectangle!)

The switch marked
[]BIS DEF ( BIS is german for through) is activated whenever the system is on ( [] through defrost), and the one marked OFF is only active when in OFF, so the same SPDT microswitch handles both of these.

The one marked DEF is only on in the defrost position, so I use a second switch placed 270 degrees away to actuate it from the same cam.

The switch marked
Off[]V is actuated in the first 3 positions, so the second cam
and switch actuate it. This is actually control for the defroster flap solenoid, which is energized when you DO NOT want the defrost flap open.

The switch marked
^V V is actuated in the 3rd and 4th positions, so the third cam and switch actuate it. This is the control for the footwell flap and is only on when you want the footwell flap open (the opposite of the defroster flap)

The other 2 switches are for the temp control to signal max heat and max AC.

If you wanted to avoid fabricating a cam switch, you could wire in some rocker switches exactly as shown in the schematic, except that you'll want the defrost switch to interrupt power to the switches for the footwell flap and defroster flap.

I you do decide to make a cam switch, let me know as I have some extra stuff from this project, including some nice stainless steel keyed shaft and some acrylic cams.


HTH,
-don

Don Ashe

Thought I'd throw this in - this is a shot of the PC board traces for the switch. You can see the arcing on mine, which is what led me to do this mod in the first place!

-don

M. Requin

Don, thanks a lot for these posts, very helpful in trying to diagnose problems I am having with the HVAC system, which I have narrowed down to the controller board. The explanation of the schematic is particularly helpful. I have also thought of replacing the slider with discrete switches, might make a good winter project, and it seems like it would be easy to test a new setup/mockup without taking everything apart, just unplug the connector in the console and plug it in the the new board, assuming use of an edge connector on the new controller (which seems like the easiest way to go). Thanks again.

hans14914

Another option is the stand-alone remote-controlled climate brain purchasable here:

http://www.roshanindustries.com/mp3pumphouse/Aircon.htm

It can also be interfaced with a USB/Serial input from a PC. It has relay actuated blower support (perfect for our 4-position switch), then servo control for mixing/and flap operation. This is where it would get difficult. You would have to make the servo drive the two selectors as there are not enough I/O on this board for stimulating the vacuum actuators. 2 linear servos tied directly to the back of the selectors would work well, but it woudl require a custom case, as they wont fit in the stock version.

Another up and coming climate solution is the new EyeR, info can be found here on that option:

http://www.mp3car.com/vbulletin/fusi...sionbrain.html