Climate Control Display

This past week my 2004 C4S decided I was no longer worthy of one of the pixels in its climate control display and thus took it away. Here's a picture of the display set at "66" degrees. I circled the missing pixel. As you can see, the unit itself is pretty much immaculate (save some dust) and this is the only problem I've had with it (no sunsetting, etc). Anyway, I reached out to a couple of the companies who sell replace LCD screens and one of them said they thought it could be the LCD itself or that the graphics chip solder might be coming undone. I'm guessing that there's no way to know which might be the culprit without opening it up, however, I was wondering if any of you who might have more experience with the problem might have any thoughts? Is it common for the solder to break on these units? I've read/heard about the LCDs being a weakness but never the solder to the chip. Is the latter an easy fix for a soldering novice? Generally speaking I hate working on electronics but the LCD fix seems straight forward enough. Breaking out the soldering iron, however, has an intimidation factor to it. Any thoughts would be greatly appreciated. -Eric P.S. For those who might not know, 914Rubber.com sells an LCD that replicates the OE graphics.

My info is it a segment, not a pixel, as it represents one finite item of an alpha/numeric character and not just a tiny part of the character. Look very carefully at the display to see if you can see any signs of well, I'm not sure what it looks like having only seen this a time or two and not in the last 10, errr make that nearly 20 years or more, but what you are looking for is sign the liquid crystal has leaked its fluid. If it has the display is bad. If it has not then my WAG is there is a bad solder joint. You might be able to carefully, very carefully, reflow the solder and resurrect the segment and the display. Maybe. You'll have to remove the display and expose the innards. The segment solder connections may not be that apparent or even accessible. I've never had one of these A/C LCD panels apart but I've had other dedicated LCDs -- with segments, ICONs -- apart and the LCD is flow soldered to the PCB and there is no access to the solder joints.

Agreed with Macster. These things are generally wave soldered, not individual solder joints like you see on old-school circuit boards. If you were to try to fix this with a Radio Shack soldering iron, you'd likely make it worse by shorting out the adjoining contacts. I think the cheapest route might be to post up in the Parts Wanted section. Maybe someone is parting out or track converting their 996 and doesn't need the climate control unit...ebay would be my next resource, and a last resort would be emailing the used parts places, which can be spendy.

Actually, I may be wrong. I tore into an LCD here at work and it is quite different than I remember. The LCD plate or glass has conductive fingers which lead to the various segments/ICONs. The fingers run along the top and bottom border of the glass. The glass is held in a metal frame. Special pliable material (neoprene?) strips with conductive material in various regularly spaced locations are then held in place on the tabs. (The tech referred to these a zebra strips.) The strips then are contacted on their other face by conductive metal fingers on the PCB. Except for some resisters and such on the back of the PCB there are no solder joints to speak of. Power and ground and signals are supplied through a connector on the PCB. There is a back light panel which is illuminated by LEDs. The crystals need light to be easily seen when turned on. Regardless, you will probably have to disassemble the A/C LCD unless you can find a picture of one already disassembled. Keep in mind if you do decide to tear into this -- so to speak -- you want to be very careful. You can end up rendering more segments/ICONs dark. I may be wrong again but I believe you'll likely find no way to resurrect the LCD. Check out this link for some pics of the A/C LCD panel apart. http://www.cafr.ebay.ca/itm/Porsche-...item256cfad4ae Based on what I see you are not going to repair this, but it can be replaced I guess.

Good god, it looks like 1970 in there. If they are all contact joints, just wiggling the back of the assembly a little without taking it apart might be sufficient to wear through whatever oxidation is preventing the contact from...contacting. It's also still possible that the whole segment is dead, but pulling the climate unit out of the dash and wiggling its bits is worth the effort... You could also ignore it completely by setting the temperature to any number ending in '2.'

I've had this thing apart multiple times. It could be the "zebra" separating from the lcd. It's just a pressure-contact multiple conductor connector on either side if the LCD. 996_climate_control_LCD 015 I've got lots of pictures somewhere. If it turns out it's a bad LCD (which is common), get a replacement from http://www.914rubber.com/ He's got a great LCD that looks like the stock display. That's what I have in my car.

Yep. Just pull the rubber contact ribbons out, clean both ends with alcohol and reinstall. That should fix your problem.

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FYI, I originally installed this "Audi-style" LCD in my car when the original climate control LCD failed. Then I found the OEM style replacement from 914Rubber.com. The OEM style looks much better . But, anyone is interested, I have a used "Audi-style" LCD panel for sale! Cheap!

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I believe that's the LCD based on the Audi graphic. As frisbee also noted, 914rubber.com sells an LCD replacement that's true to the OE graphics. Got it but that's my question. How do I know if the LCD is failing? When you say "zebra" I think "zoo"...or Chris Rock playing a zebra wearing an afro. Is this something an electrical novice can do easily? Understand that I've never had this thing apart before and I can't visualize what you're talking about. But it sounds like you think it's an oxidation type of issue...just clean the connectors and it should be fine? That much I understand...assuming I understand what you're saying already. lol -Eric

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I have some DIY info in a word doc I could share. PM sent.