Re: Power window problem, very hard to diagnose for this new guy

Hello, Pedro and everyone,

This is my first post on this forum board. Thanks for the opportunity. I just bought my first Porsche. It's a 2002 Boxster S. I got it very inexpensively, however while it looks great it does need just a bit of TLC. The biggest issue is one that I had originally thought would be a 30 minute diagnosis and $5 fix. The power windows are up and they don't move. The windows are driving me nuts. I’m not good electrically. They just plain don’t work. They do nothing. I tried with the power window switches, they don’t work. I tried with the key in the door. Nothing. I checked both the fuses - they’re fine. The passenger door window will occasionally drop very slightly when I open the door, but not usually. It happens randomly. I had disconnected the battery for something and when I hooked it back up, the drivers window dropped smartly for exactly three times that I opened the door. Then it promptly went dead again. I have looked at all the posts on the internet, and a couple of guys have tried to help me briefly. Some mention the interior lights, and the key remote locks as having something to do with it. Neither of those work either. The horn, which some people occasionally mention, does in fact work. Some tell me to look at the immoblizer. I know where it is, but I don’t know what I am looking for once I get it out. Also some say to look at the pins inside the rubber booted connection inside the door jamb. Do you know what size screw holds that rubber boot on at the bottom? I don’t know where to start checking for voltage. I don’t know where these micros witches that I read about are, and what they do and how to check them. I don’t even know how many there are. Perhaps they have something to do with two dead windows? I doub't it, but stranger things have happened. I spent $ buying the Bentley manual. It has zero information on trouble shooting the system. I’m lost. Any ideas on troubleshooting this crazy thing would be hugely appreciated. Also, if it is the immobilizer, what are my options? Ideally I would prefer to just bypass it, but I guess that's not possible. There is a guy in Florida that I spoke to. I could mail him the whole locking box from under the seat as well as a key and the main computer form the car, and he'll set it all up again and mail it back to me. The problem is it's a $875 service!!! I was hoping to minimize that. Any and all ideas are gratefully requested.

First check that your battery and alternator are good, Battery should read at least 12,5V with ignition off, 11V when cranking and 14V when idling. All kinds of electrical gremlins pop up when the battery gets weak.

Thanks. I checked that, battery and alternator read good.

the parts listing for specific models that Porsche publishes. It has diagrams to help you see how things fit together.

Available online here for free. Go down and enter your model and then download.

I didn't know about that, but thanks to you I do now. Thanks!

... or Central Locking Unit under the driver's seat controls the power windows, the soft top, the door locks, the alarm, and the immobilizer.
If your CLU got wet, that's where I'd start looking.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

You were right, Pedro. I opened it up and it was previously wet and now corroded. I sent it to Colorado for repair and get it back shortly. Hopefully it works well.

Very similar problem as Doug. '97 986. Put away for winter, everything worked 100%. Replaced the Immobilizer unit last year, including a waterproof case. I have a spare Immobilizer, as I got a 2nd DME & Immobilizer programmed when I had the first one rebuilt. Battery Maintainer got unplugged over winter. I recharged the battery and replaced the maintainer. Opening up the car for spring. The windows & locks don't work.
Locks
-with fob: Lock, Unlock, Beep. Trunk Works fine
-with dash switch: nothing
-with key: works, both doors, however the alarm light doesn't illuminate
Windows:
-Both Inner & Outer Door Handles: No window movement, can hear relays in doors click
-Console Switches: No movement, hear relays in doors click
-Top Retract & Extension: No window movement. Top works fine.
-w/ Door Key: No movement.
-w/ Durametric, courtesy window actuation, relays click, no movement.
Interior lights work fine.
Immobilizer Fuse, C3 & D1 are 100%. Battery & Alternator Check fine. Have tried battery disconnect to no avail.
I'm thinking Top Latch Relays or Immobilizer Unit.
Suggestions or ideas please. Thank you.

Immobilizer is swapped out. No change.

Update 3/26/22
I inspected the A Pillar Door Loom connection. All looks good, used electrical grease in the terminal connections and sealed the outer casing when re-connecting. Replaced the Top Latch Microswitch assembly with no change in lack of operation. Two new Door latches arrived, Replacing those in a week or two. Will inspect handle switches and motors/regulators when the doors are opened up.
Will update with what I find.

I still need advice, tips, tricks or information on potential root causes. I hate trouble shooting by throwing parts at a problem.

It still sounds to me like the CLU is at fault.
I'm not fond at all of the waterproof case for the CLU ... because it's not ... waterproof.
I think you're calling the Central Locking Unit the Immobilizer.
The Immobilizer is actually a function of the CLU (when it doesn't recognize the key in the ignition) and doesn't allow current to the coil packs.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna