Derek Pedersen

While reading about the cool PDAS functionality on the forum, I came across some interesting threads about making a green PDAS light functional in one of the gauges. Apparently Porsche added in the provision for a green PDAS light to turn on / flash whenever the PDAS engages (same as the yellow LED by the switch, but MUCH easier to notice). It appears they decided against the function because cars were not delivered with bulbs in the the spot for the green PDAS light. Someone figured out that adding a bulb would make the light work. Except it didn't in my car and apparently in a few other cars as well, so I decided to dig a little deeper to see what the problem was.

Turns out the fix is very simple. My car is a 1990 C4.

Hope others will find this useful.

I perused the wiring diagram for my year and located the PDAS wire (wht/blk) going to the gauge. Found which connector the wire came in on and checked the corresponding pin on the gauge. Turns out on my gauge the pin for the green PDAS light was under the OTHER connector. Probably a mid-cycle design change that Porsche let slide because the light was non-functional anyway.

So, all I had to do was move the pin from one connector to the other (pin II/6 to I/7). Works great. Can't wait to see it in action this winter.

Pictures are in sequential order showing me modifying the pins. Sorry no captions, but easy enough to follow.

Here's how it looks.

mojorizing

Interesting....
You moved wire II/6 to I/7 to light window #10 (PDAS), nice....
Do you know what is window #6 (where II/6 wht/blk was connected) if it lit up? The schematics for the '89 C4 has window #6 as an empty field - not even a "not used".
Nice write up!

Derek Pedersen

Good catch. I meant to add that into the post (and now I have).

When I tested the pin where II/6 connects, nothing lit up on my gauge. On the schematic I'm using, it shows II/6 (wht/blk) connecting to window #4 (green PDAS). But in fact, I/7 is connected to the green PDAS window.

All other lights that are supposed to be functional from the schematic are functional. The pins for II/6 and I/7 were the only discrepancies I found.

August West

Very interesting post...I also have a 1990 C4 and I'd love to hear more discussion about this as I've never seen any PDAS light lighting up whenever the PDAS system is working overtime as it is supposedly designed to do so. I always thought it was one of the little LED lights down by the PDAS switch on the center console that was supposed to light up but have never seen them light up.

tbennett017

Help me out here... is the goal to have a dash light go on when PDAS is engaged? Is this not the same as the LED on the lower console? Just trying to get a clear idea of what you're trying to accomplish...

(This might be different on the 89 cars, but on my 91, I get the LED on the lower console when PDAS engages- I can see it at the corner of my eye...)

Unkle

I have a 1992 registered car and it also has the light by the centre console that lights very occasionally. I suppose having it more in your face is more like the modern cars i guess (my Audi has that ESP light on the dash).

August West

Which LED lights up for you and what kind of maneuvers make it light up?

FeralComprehension

There's a small amber lamp below the PDAS control. I can light mine by nailing the throttle on dirt roads, or as I'm cornering hard on wet pavement.

DWS964

The key point here should be - if you are driving in such a manner or conditions that lead to the activation of the PDAS system, then you should NOT be taking your eyes off the road and looking down at the itsy-bitsy little yellow LED by the PDAS switch. The green light for the PDAS on the dash will be easier to spot, without being distracting. This is certainly on my list to-do. It's a nerdy 964-geek thing.
Have Fun, Be Safe

daniel94

Nice job Utah...now I want to do it too...

Derek Pedersen

I modified my original post to show the background of what I was trying to accomplish. For some, adding a bulb makes the light functional. Apparently there are others like me that have the blk/wht PDAS wire, but aren't getting the bulb to light.

I've got the lower LED as well, but didn't even realize it was lighting up until I read about the green PDAS light on the forum. The green PDAS light comes on at the same time as the yellow LED. Definitely more visible.



You may only need to add the bulb. Easy to check, just move one of your other bulbs to the PDAS spot and see if it works. If not, check your connectors and see if you've got the same scenario as me. If you do, this mod should work. It really is pretty cool to see it light up in fast corners. And I'll be able to tell for sure if my "PDAS disable" theory is legit.

FeralComprehension

Full report please!

(And if you can figure out how to re-enable it after hooning around, that would be cool too!)

frankvan

https://rennlist.com/forums/967760-post3.html

utah,
in your last pic your gauge shows a green light in the top left "corner" of the gauge. The PDAS light in mine is two over (window 3 viewed from front, or window 2 viewed from backside) and is a pictogram of 4 wheels? (as per garrett's pic in post above).

August West

The link in frankvan's post is pretty telling...Whereas Utah's newfound light looks more like an ABS type icon, the one in frankvan's link looks more like a traction-control type of icon.

It may be that Utah has done most of the dirty work and would only need to move the wire once more to light up the more appropriate traction-control light.

Wouldn't this be the perfect time for St. Adrian to weigh in?

Utah still gets the Geek Squad award for bringing this to light!

-nick

I'm wondering - would putting a bulb in Utah's spot (before he changed the harness pins) light that space when the ABS kicks in? Since it looks like a brake-type icon? That would be an interesting mod.

What are the icons in the other empty spaces on that gauge?