Chuck Schreiber

Well,

Full bore into finishing all the little things that are bugging me on the interior including the broken sliders on the HVAC head unit and bulbs on sliders that don't illuminate. Process of removal seems pretty straight forward. Allready have faceplate off (trim) and side panels off. Parts are onroute and should be here midweek.

Now for a few questions which I'll probably be able to answer once I get in there but would like some input before I tackle later this week.

-Anything to really be carefull of when pulling this out. (BTW, its a manual unit off the 79. No auto climate control here) Marking connections digital pics etc?

Looks like central warning needs to come out. Don't think radio does.

Once it's out, is the bulb for the sliders pretty obvious? From the Tips page, looks like one bulb lights up both?

Are slider clips and sliders themselves pretty straight forward. Again, anything I need to make sure to do or not to avoid breaking the new ones?

And last but not least. I think I saw a post about a year ago showing someone had installed an LED bulb/bulbs inside the unit to illuminate the front panel itself. Is this serviceable or somthing that I don't want to get into? There's got to be at least a bulb or 2 internally seperate from the slider illum. bulb. If the slider bulbs are KO'd can't think the internal is too far behind. (25 years old at this point!) Any thoughts on replacement or modifying to the LED?

Any help greatly appreciated!

BTW, I'll document with a digital camera if anyone is interesting in me posting the procedure.

Thanks!

Jadz928

Chuck,
I'm very interested as it is the next project on the list, after fixing sunroof.

Maybe we can do it at the same time to help each other along. I need to pick up the sliders as well. I'll be placing an order shortly along with a bunch of other stuff.

Chuck Schreiber

Jim,

Sounds good. Like everything else I've done on the car, I usually learn as I go. I'll start later this week and if I'm slightly ahead I'll give you some things to look for.

zmandan

Hay guys, my temp slider does not lite up like the bottom one ether.
I'll be watching this thread for helpful info.

My "D" does not lite up. ( green lite at dash )

Should the icon at the lite turn on **** lite up like the fog lite icon?

LOL
dan z

Joel928s4

Hi Chuck, I'd be interested in seeing the procedure if you wouldn't mind posting it. Thanks, Joel

Garth S

Chuck,
Probably 2 years ago, I did basically the same to the auto climate control of an '80.
So, if the neurons line up correctly, as I recall, the most sensitive part of the job is in removing the upper consel trim. A smooth, rounded corner putty knife is a fine tool for this job: carefully pry out the top central air vents - then, slowly work down each side, inserting the knife deeply in past the trim edge, and withdrawing with firm pressure to the center. If you go too fast, Jim/Susan/.. will be getting a call for a replacement.
The central alarm bar can be loosened and pushed aside. The climate control comes our readily after disconnecting the wire harness.
To get inside the control head, for the single bulb is burried deep within, there is a screw on the top cover, and ~5 plastic tabs around the back edge. 2 or 3 of these tabs are likely to be so brittle, they're not going back in - that's what Duct tape is for.
Once inside, follow the wire to almost dead center, and there is the bulb holder. It pulls straight back. The bulb illuminates the 'symbols' and the 2 sliders pick up their meager light via optic fiber cables .
On reassembly, again, the only trick is in replacing the large edge trim - start from the bottom, slowly...
This should get you there for a std. bulb replacement - in too much detail! If you figure out the LED story, let us know.

Chuck Schreiber

Joel,

I'll post when finished. Garth, thanks for the info, it's a great start!
I've also got an auto head unit off a parts car I'll look at and dissassemble before I delve in. I'll post pics.

Thanks

atb

Hey Chuck,

Here's a pic of my LED install:



This pic was taken with a long exposure, so the illuminated sliders and **** are much brighter than in true life. That being said, they are still very bright. I'm going to experiment with trying to dim them some. Because they are LED's, I've been told that you can't really have a dim control on them, they are either on or off. If someone can confirm whether this is true or not, I'd be interested in knowing. There already are resistors soldered in line. I was thinking of just taking a black marker and darken the LED's a bit. The panel uses the stock bulb. The fiber optics to the sliders were replaced with wiring and an inline resistor which feeds the LED's which are in the sliders. The sliders needed to be drilled out a bit to accomodate the LED's. The **** is not illuminated in stock form. I ran wires out to the ****, and drilled a hole for the LED to sit in under the fan emblem which is translucent. There is slack in the wiring to the LED which accomodates the twisting of ****. All in all, a very cool set up, just a little bright right now. I've corresponded with some folks in the UK that used mini bulbs instead of LED's with good results. Might be an option. I was concerned that bulbs would get hot, but apparently they haven't had any problems, and in this way you retain the dimmer function.

Marc Schwager

Adam,

You can dim LEDs with a dimmer. It is not a nice smooth function as with an incadescent, but I have dimmed many an LED by just throwing a large (50K Ohms) variable resistor into the circuit. Maybe a few of the EEs on the board will tell us the right way to do it (without $30 of electronics and a 4 layer PC board :-).

I used that technique on my dash lights (15 LEDs on three 5 LED modules) and on a solar powered observatory I built (27 LEDs on nine 3 LED modules). I stuck a heat sink on the variable resistor on that one as it draws 1/2 an amp which means 6 watts of heat dissipation on 12 volts.

When I headed into my center console, the light bulb was fine, it was the litlle fiber optic cables that had fallen away from the switches and become frayed. I chopped them off so they were level and put a little heat shrink around them and carefully threaded them back into the sliders. I have to say, the LEDs lokk much nicer

Chuck Schreiber

Adam,

Very trick. I thought about doing the fan switch as well. At first glance, it seems like they (Porsche) almost thought about doing it but scrapped the idea. BTW, are minibulbs direct plug ins or do you have to do mods to them? Let me know. Thanks.

ajmarton

I was wondering - what is the key symbol for? Mine never lights up.

Garth S

If it's working, that is the 'central locking' button - one touch, and doors lock/unlock., IIRC. It's function may depend upon where the round ***** on the upper rear of the door panels are set.

Steve J.

You can vary the intensity of the LED by varying the current with a trim-pot (variable resistor). Make sure you don't exceed the maximum current rating of the LED. Have a fixed resistor in series with the trim-pot so that when the trim-pot is adjusted for minimum resistance (dead short) the fixed resistor limits the maximum current through the LED. 50-100K is probably a good value for the trim-pot.

atb

Chuck wrote:

This was another issue I was concerned about. My limited understanding of electronics tells me that the draw of the three LED's is nominal, where as adding three additional bulbs would be a significant increase in the draw to the light bulb circuit. The LED's are wired in series with the panel bulb. IF you went to bulbs, I imagine they would be wired in series as well. The bulbs would have to be hard wired.

atb

Regarding the fan **** being set up for illumination, I think you're correct Chuck. Initially, I replaced the stock fiber optics with some bigger fiber, and ran it to the **** as well. It wasn't bright enough for me in the sliders, and was too concentrated in the **** (and too dim as well). I think that's why the factory passed up on it, it looked kind of silly having this pin point of light in the middle of the fan emblem. Could you imagine what it would have ended up looking like if Porsche was commited to making it work Porsche-style? I can just see a **** twice as deep to house the huge porsche designed mirror reflector built into the **** base to disperse the light of circa '77 fiber optics.