Bill Ball

Thanks Ed! I haven't found it yet, but that blue plug should be easy to spot. It is the same alarm controller as 89 but I don't see the crossbar it should be tied to. It must be covered up. The box Alan mentions, located in the center console near the "timing" (buzzer) relay, is an auxiliary alarm box. I checked that out yesterday. The other harness I found with the frayed wire leads up to what I think is the bulb monitoring system. Headed out to the car now.

Ed Scherer

OK, think I just found it. Open up your glove box. Look on the right side, right in front of (an inch or two toward you, i.e., toward the rear of the car) the damper.

You'll see two nuts there. Those are the ones holding the alarm unit in place; you can see those nuts attached to the unit on those photos I just posted above.

IIRC, it's not too hard to remove the furry trim piece that covers it, but then again, I had my glove box off at the time, so perhaps that's a prerequisite.

And maybe if you remove those nuts, you won't even need to remove that trim piece; it might just drop down if there's room for it to escape.

Bill Ball

Ed:

OK, it's not BEHIND the glovebox. It's BESIDE the glovebox, to the right, attached to the bulb control unit. You don't even need to remove the glovebox. I did remove the carpeted trim piece to the right of the glovebox, then the 2 nuts you mentioned. This is completely different location from 89 even though the WSM suggests it's the same location, BEHIND the glovebox.

The frayed harness goes to the alarm, so I think I found it. The fraying is due to rubbing on the glovebox over the years. Hopefully good news will be posted soon. So, it COULD be a frayed wire in the alarm harness has been causing the passenger window to go down. If true, file that one away for future reference!

Bill Ball

BACK TO THE DRAWING BOARD.

It's not the frayed wire I found or the alarm controller.

Bill Ball

Here's my take and request.

Since the problem is the pin switch feed to the window controller, I need to know where this circuit gets its voltage. The wiring diagrams don't show any clear link. Here are the relevant diagrams again.

I pull the light relay..no change.
I pull L connector off the CE panel...no change
Pull the timing relay...no change
Unplug the alarm module...no change
Pull every fuse and there is no change until fuse - the window fuse

Ed Scherer

Bill, I think you've already indicated all of the following stuff in previous posts, but I wanted to trace it myself just so I'm up to speed on this.

Tracing the pin switches for the doors shows this:

• The "grounded when a pin switch is closed" wires are color coded BR/WT.
• CE terminal L12 ties together the pin switches and some other stuff. It's a good test point.
• A closed pin switch should ground terminal "T" of relay XIX (inside lights).
• A closed pin switch should ground terminal 15 (which is evidently also pin 5 of some connector) of the window/sun roof control unit.
• A closed pin switch should ground terminal "D" of timing relay (a relay that's below the radio, I think).

Is all this correct, as far as you know?

Bill Ball

Ed:

Yes, a closed pin (door open) will send all those test points to ground, if, as Alan noted, the battery is disconnected. If the battery is connected, I see about 400 Ohms and my meter's continuity buzzer does not trip.

The problem is when I break ground (doors closed, all pins open), there is enough current flowing in the circuit to activate the window controller via pin 15. Pin closed (door open), I see only 10ma. Close the last door (or hold that door's pin switch in), it goes to 100+ma (and 12V) at all the test points you noted, and the window controller emits a loud relay click and I have established it is not a controller fault.

Ed Scherer

OK.

Q: Is the one and only problem still the one you described in post #1 of this thread?

Regarding the resistance: you generally can't test resistance on a circuit under power (current already flowing in the circuit can't be separated from current being applied to test resistance!)

Q: What are those currents you're describing? Current flowing through the pin switch? If so, that's somewhat helpful; I could measure mine and see if they're the same. That ~100 mA looks suspicious, though, unless it drops to a something substantially lower after the time delay expires and the interior lights go off. I.e., you should not see that much current flowing anywhere when the car has reached steady state with all the doors closed (IIRC, my car shows about 35 mA through the battery ground strap once everything is turned off and the interior lights timer has expired). I think that's about normal.

A few more questions (and sorry if this is repeating what has already been said earlier in the thread, but I just want to make sure):

• Q: Does this "passenger window goes down on its own" occur with ignition off? Ignition on?
• Q: How hard is it to get to the window/sunroof controller? It's under the driver's seat, right? Do you have to remove the seat? Just in case I want to do some measurements this weekend and establish "working values."
• Q: Why is it again that you're so focused on this "pin switch" part of the circuit? I just re-read a bunch of earlier posts and I'm not convinced that there's really anything unusual going on with that part of the circuit. Generally, if you have a switch between something and ground, you really can't draw any conclusions (again, in general) about what voltage that something should be with the switch open.

Just a few other things to contemplate (before going into a really exhaustive, rigorous diagnostic procedure) — some of which might have already been mentioned:

• Since that timer relay is close to the radio (which might have seen "maintenance" in years past ), one of the wires to it may have been pinched and might be shorted to ground or another wire.
• The fact that the pin switch (and related) wires are color coded BR/WT and that they're grounded when the doors are open raises the likelihood that someone may have tapped into these wires somewhere thinking that they're a full-time ground. If so, attempting to use this wire "as a ground" by some other circuit (particularly if it draws a lot of current) might cause trouble. Q: Are there any such circuits that have tapped into the BR/WT wires anywhere?

Alan

Bill - I still don't believe this 12v thing is the issue - but the interior lights relay T pin is what should be pulling it up.

I don't believe for a moment that it can source any significant current @ 12v - so I'd believe its causing something else to switch perhaps - but the sense is all wrong. when it is 0v is when it should switch the controller on - 12v should eiether do nothing OR switch it off depending on the controller mode (ignition on & power retain mode or not).

Go back to my post with the pin configs - can you test each pin in the following cases: (somthing else is screwy - if it is related to the pin switch its NOT just that)

1) Ignition on (e.g. controller should be fully on)
2) Ignition off - door open (e.g. controller should be in door overide - partial functionality mode)
3) Ignition off - door opened & closed (e.g. controller should be off)

Particularly do you see a solid ground on the ground pin and a good (non drooping) 12V batt on (30) and correct switched ignition on (15)

Is the lock input high (~12v) and the door pin switch at ~12v with the door closed and ~0v with the door open.

What are the swindows/sunroof switch inputs doing?

Sorry - I know this is a lot of work - But something else is going on here...

Alan

Ed Scherer

This whole "pin switch" question is only a matter of establishing the state of pin 15 on the controller, right? And isn't that just used to disable window/sunroof control with ignition off the first time a door is opened? The more I think about it, the more I don't see how this could have anything to do with the "passenger window is stuck rolling down" problem.

Seems like it would really help a lot for me to just get my window/sunroof controller out and measure all the voltages with the unit at rest. And then maybe in various other interesting states.

What makes this thing so damn complicated is that there is so much common circuitry both on the input side (note that two out of three wires is common for the three input switches) and also common and interrelated circuitry on the output side, making it harder to test each input or output in an isolated fashion. If you disconnect one thing, you can't be entirely sure what impact it might (should or shouldn't) have on everything else.

So how hard is it to get to the window/sunroof controller? Sounds like something I could do over the weekend.

Alan

Ed you can reach it with the drvr seat all the way forward - this is certainly adequate to plug the jumpers - may be a bit awkward to measure voltages too... It may be a little easier to do standing on your head naked - now I come to think of it...

Alan

Ed Scherer

OK, I'll give that a try.

Everyone will want photos, right?

Alan, what do you know about the various inputs (13-26)? Early on in this thread, Bill posted some voltages for the switch inputs; any idea what the nature of these inputs is? (High impedence, etc.)? I notice that there's what appears to be a SIP resistor pack near where the inputs come in on that photo of the controller that you included in post #77; I'd hoped that perhaps that was a pull-up for inputs that would then switch to ground. But the voltages that Bill posted in post #4 really left me wondering what the heck was going on with inputs. I was hoping that maybe the commons (black and green) were either 0 V or 12 V, with red providing momentary connection to either of those, but it appears that it's not so simple.

Ed Scherer

Alan, you're right. I moved the drivers seat all the way forward.

Found 32¢ (one quarter, one nickel, two pennies).

Then I found (under a rectangular piece of carpet that was entirely covered with a piece of blue plastic: is this normal?) a black unit labeled 928 618 240 00. Window/sunroof control? I'm thinking, "yes".

Looks to me like it won't be difficult for me to get it out of there. Looks like removing one nut (and possibly one Phillips screw, if necessary) will free it. And it looks like there's enough slack in the harness (assuming it's not fastened really well) to allow sliding it rearward far enough to get to the connectors (which are on the side of the unit that's toward the front of the car).

Don't want to do it this evening, but during a quiet period sometime this weekend, I'll take a bunch of measurements and see if I can do a good job of characterizing what's "normal" for this unit.

Alan

I'd expect thats what they should be not obvious why Porsche would have done any different. The 12v switch side may be switched by the controller of course - but I'd expect the ground connects directly to one of them....

Bills numbers were odd and I never actually measured these... but logic says it should be simple obvious stuff..

I'd assume the inputs from the switches should probably be resistor biassed to approx 6v so they can detect either a high or a low as switched and I'd suspect this is the cause of the pass window opening (e.g. resistance on the input - wiring since removing the switch made no difference)

Interested to see what you find.

Alan

Mrmerlin

Ed the blue plastic is a facotry cover thats supposed to get pull prior to delivery, it is so buried that no one ever sees this, so only the intrepid investigators will find it, , I found one in my 88 when I removed the seats