996 Drivers Side Seat Failure ? HELP...

[yale1066]

I was just giving the 2000 996 Carrera 4 Cab a nice clean after winter and it "seems" that the drivers side seat has jammed in a full forward position (totally undrivable). I moved the seat all the way forward and up to vacuum the rear and when I tried to return it to normal...no movement. Never a problem before...checked fuse... blown (it had a 40 amp instead of 30 amp in the fuse panel....previous owner ).... hmmm. Replaced fuse with a 30 amp...blows again.

I think I hear the motors (a clicking sound) trying to move the seat...with a unfused jumper wire (careful...) and the lumbar control works. So I've got power...I guess ?

Motor(s) ?....control switch(s) ?......is there a blown relay somewhere ? Remove seat ? I can't even get access to the front rail bolts, as the seat it fully forward.

HELP.......

[yale1066]

More info....Got some new 30 amp fuses. They don't blow...WTF ? There is some clicking sounds (switches ? motors ? relays ? I can't tell....tried to hold each motor under seat to feel vibration) when I engaged each seat control. Lumbar works fine. But can't tell with others.

There is a possibilty that there is "something" jammed in the seat rail "teeth"....tunnel side. Found a literal "coin collection" from previous owner slid UNDER the back of the seat rails. Used a paper clip to push out visible ones. But I can't see any obivous jam........yet.

How much access is there to the right side of the seat rail when you begin to rip apart the centre tunnel stuff ?

Or....can I bypass the memory control "circuit board" by accessing the panel directly beside the seat ?

[Jamikest]

Seat fuses blowing is almost always something jamming the rails. Pulling the center console won't give you much more access to the rail. I have found replacing the fuse with a fast acting circuit breaker and then rocking the motor switch can help un-jam it. The fast acting breaker is for testing/repair purposes only! Do not leave it in!

Never, never, never run a seat to full stop and hold it there. This is especially true on 993 and older bodies. Usually only a coin or suck item in 996s causing a failure. Older bodies would explode the drive cables when you pull such 'shenanigans.' Yes, I learned the hard way and fixed my first oops for free

[yale1066]

Thanks you very much...I will give it go. Sound like a two person job... "Honey can you help here for a bit....???"

To confirm from my previous post I replaced the fuse with a brand shiny new one....correct 30 amp....and presto...it didn't blow.

Off to the carport. Cross your fingers.

[yale1066]

I have a wonderful new coin collection....who knew a seat could contain such wealth. Wifey played with controls as I shook the hell out of the seat. But....no real progress.
So I took out the nearest drive cables at rear of seat....they control the "tilt". Used a cordless drill with the drive cable to tilt the seat back to "normal". Just trying a few random approachs. Tilt motor runs free with seat control switch now, but only in one direction. To me it seems that there is a central axle running laterally under the seat with sprockets that drive the "forward-back" position. Difficult to see clearly. Perhap with a vice-grip (carefully) and with lots of time.....I can rotate the axle manually to gain access to the front rail bolts....then remove seat ? Then check for fried motor(s) or other ? Thoughts... PLEASE.

[yale1066]

Well...after poking around upside down from the rear of the seat...I discovered that the tunnel side front rail plastic trim jammed its way into the rail and cog system. Perhap this was the initial problem....but alas removable with very long needle nose pliers has made no difference. I have tried to rotate the lateral axle to gain access to the front track bolts to body with pliers...but it is rock solid. I am considering accessing the two front bolts from under the car. Two .075" holes can't be all that bad ? Body plugs after ? Accurate measurements are a must. I will use the passenger side as reference. I am out of my mind?

[Jamikest]

Wow. Thats some severe stuck going on.

So drive undone, and still cant turn it? You know you are going to find it as soon as the seat is out. But how to get the seat out without killing it. Hmm.
The only thoughts I am having involve the destruction of the seat adjuster assembly.

Does the motor even click or attempt to move at this point? When you toggle the fore-aft switch, are you getting ANYTHING? I would still rather see disconnection of the motor and attempting to drive it... but I don't know if thats even possible with the seat all the way forward.

If the motor clicks or attempts to move- then you are still bound by something in the tracks.

If the motor is completely silent and no movement, you may have further issues.

GL

[Wayne 962]

Can you post a pic of the current access that you have? Maybe I have a tool in my collection that will reach. I do have some weird stuff...

-Wayne

[mother]

I commend you for your perseverance on mine the motor was the problem with some metal particles jammed in the gears and the only remedy was motor removal and inspection. Hope some of the images help but once the motor is removed you can hopefully move the seat with pliers etc and should move freely unless something else is binding. GL

[yale1066]

Thanks for the pics Mother. All looks very familiar.....now. I took a number of photos myself for reference...not really enough....and have had the seat almost completely apart. Came back together again fine. Will post pics.

Taking the seat out was frankly hellish....about 4 to 6 hours on my back with a variety of nasty electric cutting tools....think 4.5 inch grinder.

Eventually I tested each drive motor and the "transmission" system , and have worked my way back electrically to the female plugs that go into the "black box/memory". Used a battery charger on a 2 amp setting to check for movement etc. both ways directly to the motor and then to each of their respective female plugs. All motors and drive systems work great...now. I believe the seat back motor system had some how gone "past" its ability to reverse itself mechanically.

My current problem now is....where do the four plugs go into the black box? My reference pics are not clear enough. The male connectors are labeled 10 through to 1 left to right on the box and some are used for power and to go to the control switches. If I can plug them in these respective spots I can narrow down any other issues. Is number 1 used...? I just hope the memory box is not fried....

[mother]

Pictures worth a thousand words. If I am not mistaken inside the box there is a fuse and the box can be opened with care by lifting/prying open the locking tabs. I ended up bypassing the computer with straight (DPDT) switches using just power and ground from each plug.

[yale1066]

Thank you Mother for the very clear pics ....yes indeed.... pictures are worth 1000 words.

During the seat tear down and rebuild I was stupid enough to lose track of the three coloured labels (green,yellow and blue) ...Since the wire colours are the same ...what specific motors do the green, yellow and blue labels represent ?

[mother]

Sorry can't remember and the schematic gave me no clue, however you should be able to just connect them one at a time and test by moving the seat switch before mounting the seat. There are other resources/forums that have a great deal of knowledge if not already familiar.

http://www.renntech.org/forums/index.php

http://forums.rennlist.com/rennforums/996-forum-60/

http://www.6speedonline.com/forums/996-11/

[yale1066]

Thank you for the other sources. Any electrical engineers out there?

Before I consider a "new" memory computer board or something more radical... here are the facts:

2000 my 996 Carrera 4 Cabriolet (US model)

1. All seat motors work when given direct current to their female plugs - both in
forward and reverse modes.

2. I connected all 3 sources of power from the cars electrical system to
the memory computer (# 6 and #7... and the monster one to the seat
wiring harness). Main fuses ok. Grounds looks very clean and good.

Then I connected # 9 seat switch control plug to the memory computer
(white,blue,black).

There is only power at the centre small male "plugs" on #1, #2/3, #2/3, #4
(right to left on the memory computer) when seat control switches are
engaged, but consistent power to # 8, 9, 10 (larger spade types) without
touching seat controls. Connecting each seat motor connector to the memory
computer does not engage seats.

3. I do not see any fuse that I am familar with inside the memory computer.

4. There are definitely relays being tripped on the seat memory board when seat
control switches are engaged and when I checked for power at # 1, 2/3, 2/3, 4 with a circuit tester.

[mother]

I am curious do your side view mirrors work with the computer disconnected? I replaced my computer on my car and did not solve the problem even when all motors functioned so I chocked it up to being the seat switches that's when I said screw it. Are you saying that NONE of the seat switching moves the motors it maybe hard to tell since the motors do not move rapidly? Just a suggestion you can get a good used computer at a recycle place and they may even let you try it first if local.

[yale1066]

That's an interesting idea about the mirrors. I will give it a go....tomorrow. I now understand how to do a direct bypass using three way toggle switches (dpdt?)

I'm Canadian...living in Ontario...about 2.5 hours North-west of Toronto.
Not too many Porsche boneyards in my part of the Great White North.....one about 2 hours away. Saw one memory computer on e-bay for about $350
I still think this is insane problem to have.

Perhaps I should consider using a wiring harness from a passenger side seat.
I have not examined mine yet.

Do the seat control switches all just stop working altogether...or do they slowly begin to get a little fussy ? All of mine were working just fine until the spring cleaning began.

[yale1066]

The drivers side and passenger side mirror work fine with the "brain" disconnected... that is using the electric manual controls work just fine.

I have put the seat back in...and am waiting for a response from a "local" Porsche wrecker "9appart" or (something like that...just West of Toronto) Anybody have any opinions on them...good or bad ?

I would prefer to use something simple like the wiring harness from the passenger side seat, and forget the "memory seat brain"....but the airbag warning light is now on...and I am wondering about what other function this magical "black box" does.

Does anybody out there have any direct knowledge of using a passenger side harness on the drivers side in this situation ?

[Jamikest]

That module essentially controls everything seat and mirror related. I have never tried eliminating one, so more specific than that - I can not be. It takes inputs from the seat switch, and controls the outputs to your seat. Other inputs include potentiometers in the mirrors and the seat motors.

You have an airbag light on now due to having the seat belt receiver unplugged in all likelihood.

[nphra]

Hello guys,
Have you all solve this nightmare yet..? I'm having the same problems with the power seat failure on both side of my porsche carrera. PLEASE advise me on how to fix this problems. Thanks

[nphra]

Originally Posted by yale1066

Thank you for the other sources. Any electrical engineers out there?

Before I consider a "new" memory computer board or something more radical... here are the facts:

2000 my 996 Carrera 4 Cabriolet (US model)

1. All seat motors work when given direct current to their female plugs - both in
forward and reverse modes.

2. I connected all 3 sources of power from the cars electrical system to
the memory computer (# 6 and #7... and the monster one to the seat
wiring harness). Main fuses ok. Grounds looks very clean and good.

Then I connected # 9 seat switch control plug to the memory computer
(white,blue,black).

There is only power at the centre small male "plugs" on #1, #2/3, #2/3, #4
(right to left on the memory computer) when seat control switches are
engaged, but consistent power to # 8, 9, 10 (larger spade types) without
touching seat controls. Connecting each seat motor connector to the memory
computer does not engage seats.

3. I do not see any fuse that I am familar with inside the memory computer.

4. There are definitely relays being tripped on the seat memory board when seat
control switches are engaged and when I checked for power at # 1, 2/3, 2/3, 4 with a circuit tester.

Hello Yale1066,
Have you fix your problems yet. as i'm looking to my memory computer ans it is the same one as your, so PLEASE advise me with how you fixed your. Thanks