garrett376

Every since getting my "new to me" C4 widebody, I've never had my seat in the proper position because 2 out of the 4 directions on each of the seat adjustment switches didn't work. Drove me crazy!!! Until tonight, when I decided to get at the source of the problem. Now, new switches are about $50 each.... but being way over my acceptance level on 964 spending, I wasn't about to try to buy another part! I think my wife has a block on all Porsche parts web sites...

Anyhow, the switches are very simple, and their failure to move in certain directions is entirely due to arcing inside the switch that leaves crud (yes, the technical term) on the contacts. Because the motors pull nearly 20 amps at full voltage, they arc a lot. The disassembly process is quite simple. The seat doesn't need to be removed, although it is recommended as one way to get at the power plug so you can work on non-"live" switches. Also, I cut the zip-ties on the underside of the seat to allow me to pull the switches out from the seats further to manipulate them.

Removal of the switches involves removing the two face plates. The switches are popped out from the bottom - you can see the two tabs that permit the switches to be extracted from the front.

garrett376

After the switches are popped out, they are popped apart. There are four tabs that will release the rocker cover. Be careful that you open it up with the rocker facing down, because as you can see, there are four little *****, and four springs that are really easy to lose. I had to go searching under the DME metal panel to retrieve one of those buggers!

garrett376

The crucial part, now, of the operation is the contacts inside of the switch body that is still attached to the wires. Be sure you have disconnected the battery, or removed the seat switch plug since it's easy to fry fuse #8 - yes, I am down one 30amp fuse!

Removal of the rocker switch arms is not difficult: bend the outer retaining tab and the rocker arm can be removed. The rocker arm itself has two spots to clean off the arcing, and in the switch case there are two spots to clear off....

garrett376

Here are the locations to clean (4 total per rocker arm):

garrett376

I used my little screwdriver the scrape off the burn marks on the two contacts in the switch enclosure, and the two contact points on the rocker arm. Then I just placed the arm back into the right spot and bent back the retaining tab. The trick to getting the switch back together is to keep the rocker part of the switch aiming upwards so the little ***** remain on the top of the springs. Then slide it together gently and it will pop together with the switch base. Put it all back together, and now I've got complete operation in all directions! And I save $100!

This is another example of how the 964 is such a wonderful car with its simple, non-sealed electronics that can be repaired in most cases. Excellent!

garrett376

One more thing that's helpful for those who didn't know, is if your switch busts so you can't move the seat forward or backwards which is needed to access the seat removal screws, there are two ways to bypass a broken switch. One is via a manual method using a hex key to drive the motor manually which will move the seat forwards or backwards. The other option which worked for me, was to reverse the motor wires in the event that only one direction of the switch doesn't work. That way you can move it as needed. The following view is looking at the front of the seat (under your legs)

Hambisa

Excellent write-up, Garrett. I'm sure many owners will find this DIY very useful.

craig001

Good post! I have lost those little ball bearings before on my old 928.

tj90

Garrett: Thanks for the excellent DIY.. I just used your instructions to rebuild a faulty recline switch in my 993. You saved me about $140 for a new switch with shipping.

I would also like to add that you should inspect the rocker arms and make sure the part that contacts should be straight and the tail part is slightly curved up. The part of the rocker arm that holds the metal ball should be bent up at the same angle both sides. I found that I was able to get a crisper "click" by bending those tabs to probably their original position. The tabs on a few of those contacts were kind of flattened and gave the switch a mushy feel.

I had to remove my seat from the car and assemble the spring / ball switch face into the housing from the bottom. There was no way you could reassemble the switch while the seat is still in the car.

I placed a dollup of GB ox-gard (any hardware store) on the ball/spring interface to keep the ***** balanced on the spring during reassembly. It would not hurt to put a very minute amount of this stuff on the contacts to keep oxidation to a minimum. Ox-gard contains very small metal particles that conduct and scrub the interfaces inproving conductivity. But because it conducts - be careful that excess ox gard does not cause a short...

It will take many tries before you get it right. You should feel the switch click in all 4 directions to know if it is right.

911Syncro

Garrett, thanks very much for an excellent procedure. Since I have a 968, I checked on the 968forums, and over there someone suggested trying spray contact cleaner, the simple stuff that Radio Shack sells. I had both my power seat and power window switches fail. Both failed slowly over about 1-2 weeks, ever less reliably. So your explanation above that the contacts are getting gummed due to arching made sense. Turns out I bought a can and treat both switch with the contact cleaner and they both came alive. I ain't so good with all the small part fiddling, so I was very lucky that the contact cleaner solved the problem and both are now working reliably. So I wanted to pass this alternative along to everyone in case they'd like to try it first before disassembling the switch.

The process was fairly simple. I did remove the seat switch as above, and sprayed into the small slit openings for the tabs the hold the 2 halves of the switch together. First I removed the fuse for the seats. Then after liberal spraying inside I worked the switch repeatedly to help with penetration and crud removal. I put rags around the switch to avoid overspray, then tried to empty out the excess, and let it sit/dry for 5 minutes. The seat switch took 2 treatments, but it is reliable now once again.

Thanks again for the detailed description above! The alternative of the contact cleaner wouldn't have worked with it.

swmic

Garrett - Thanks for taking the time to write this up. These type of postings are what really make this a great site!!!

Svaha

Good job, and thanks for the documentation.

kimo964

My passenger side stopped moving forward/reverse the last few years. It never bother me until I've started driving my 5 year old around recently. Searched RL, found this tread, took it part per tread, bent the tabs up, sprayed with dust cleaner (all I had)..... 20 mins later, fully functionable power seat again. Thanks Garrett!!!

Navaros911

Just did this myself this evening.... and got one additional piece of information.

After cleaning the contact points when you are putting the switch back together I was struggeling keeping everything level (preventing the ***** to fall etc...). So I realized that it was easier sticking some folded paper (multiple pieces of it) between the switch button (the large circle with the arrows) and the body of the internals. If you look at picture #5 you would stick it between the circular part and the square part.

Then slide the rest of the body (the part with the wires attached) over the part in picture #5. I didn't have a camera when I was performing the work, so couldn't take any pictures.

In any case, I saved myself $130 in just over an hour - and spent some quality time with the 964.

Thanks for the write up Garrett376

Babalouie

This is a pretty ingenious fix