Cloud9...68

I have a pair of classic gray seats from my 92 968 which, other that a little scuffing on the bottom part of the back of the drivers seat, are in near-flawless condition (yes, even the drivers side bolster), and I'd like to sell them since I'm replacing them with lightweight racing seats. But I have a problem with the power functions. Most of them were at best intermittently functional, so I took them all apart, sanded the contacts with 600 grit sandpaper, sprayed CRC contact cleaner on the contacts, and reassembled them. I was very careful to put them back together correctly, and they all spring back to the original flat position after releasing them, so I'm pretty sure the little metal ***** are all seated on the bottoms of their springs. Now most, but not all, are working again. Both of the passenger seat's switches work now, so that one's good to go. The drivers side, not so much. It's an 8-way adjustable power seat, with the switches as shown in the diagram on the right:

Attachment 600777

The front-most switch's fore and aft functions (labeled 5 and 6 in the diagram) now work, but neither of the up-and-down functions of the front and middle switch work. Most concerningly, function #8, which reclines the seat back, also doesn't work. Function #7, which reclines the seat forward, does work, and in the process of testing the switches, I ended up tilting it too far forward for the seat to be comfortably usable for most people. And the rear-most switch, which controls the lumbar, doesn't seem to be working well, either. When I press this switch in any direction, I can feel vibration through the seatback, but no real motion of any kind (not sure what's normal for this function, since it wasn't working at all before).

Since I want to sell the seats, I don't want to buy new switches, which cost over $100 apiece. Plus, I'm not sure if the switches are even at fault. Any suggestions as to what I should do next to figure out why the above functions aren't working? Thanks.

MAGK944

Can't you just swap the switches over to the other seat to confirm it's not them. If they are ok then it can only be the wiring in the seat, the cable that drives the lifts or the motors/lifts under the seat. You should be able to swap the conectors around to figure which is at fault then replace with a good used part.

Cloud9...68

Thanks; that's a good idea, except the switches are, for some inexplicable reason, soldered in, so I'd have to un-solder and then re-solder them. But in principle, what you're suggesting is a good way to troubleshoot why the front and middle switches on the drivers side aren't moving the seat up and down, because the up-and-down motion on the passenger seat is working.

jeffrsmith

If you have access to the back of the switch, you could try using a jumper wire across the solder lugs to activate the seat motor.

MAGK944

You basically have a connector at the bottom of the seat that supplies the power and ground. The switches then control that power to motors. The motors drive a cable that actuates lifter mechanisms.

You will have to get the wiring diagrams out, disconnect the main seat connector and supply your own 12v and ground to test.

Using the wiring diagram supply the 12v and ground directly to the switch terminals to operate each of the functions one at a time until you can isolate the one that doesn't work. x-ref with the seat that works and replace that part.

It's a task I know, work slowly and systematically but it shouldn't take too long.

Cloud9...68

Thanks, these are great suggestions. I have the seats out, and I have a spare battery, so I have everything I need to troubleshoot the power functions as you suggest.

Paulyy

Sorry for a slight hijack but what's (a) and (b) in the diagram? my car doesn't have it but just curious what it's for

Jfrahm

The contacts burn in more than one spot in these switches, if cleaned up properly they can usually be brought back to life. It's not just the obvious little pad contacts but the middle ones as well that need to be addressed. Kinda like a power window switch.

You can buy used switches but they are often half toasted too.

Also dielectric grease is handy for holding the little bits in place while putting the switch back together.

Cloud9...68

Paulyy - I thought somebody might ask that. "a" is the switch/controller for the seat heaters (which my car doesn't have, so they're blanked off), and "b" is the switch for the lumbar controls, which my car does have, but it doesn't seem to be working well.

Joel - Which middle pad contacts are you referring to? Could you point out what you mean in the pictures below (not sure why they're coming out so huge - I reduced them quite a bit - they're only 149 and 211 KB)? All I see in the middle of the switch is a little cylinder which has a small spring behind it, but it doesn't appear to make electrical contact with anything, especially since it was covered in some kind of grease. And yes, I used a few dabs of grease to hold everything in place while reassembling the switches. Still a PITA. Thanks.

Attachment 600925

Attachment 600926

Cloud9...68

Well, most (hopefully all(?)) of my problem appears to be the way I re-assembled the switches. Contrary to what I said in my first post, the front-most switch works perfectly in all directions, so I appear to have re-assembled that one correctly. But when I took the middle one apart, I found that one of the little ***** had moved out of its perch as I was snapping the switch back together, such that the bottom of the spring was wrapped around the perch, with its ball sitting by its lonesome in the corner of the switch body.

Does anyone have any tips for how to re-assemble these switches keeping all the parts in their designated locations as I snap the thing together? I could use the front-most switch as a test case, and test which leads have zero resistance across them as I move the switch to its four positions, and then use this information to test the other switches after I've re-assembled them, but there's such limited access to the wiring to the switch that I can't get my ohmmeter's leads on the wires, while I'm using my third hard to depress the switch. Plus I'm having trouble making sense of the wiring diagram on the side of the switch. Pretty frustrating job...

Cloud9...68

Progress! After taking the middle switch apart and re-assembling about a half dozen times, I finally got it put together correctly. I found that removing the removable white cross-bar that holds two of the springs, and holding it in position with the springs pressing down on the little *****, and then inserting the rest of the switch top, I was able to snap it together without the little ***** slipping out of position. All four of the middle switch's functions now work! So I'm now the proud owner of a 10-way power driver's seat (and hopefully somebody else will be soon, as I'm planning to sell it).

But I have one remaining problem - I can tell the rear-most switch, which controls the lumbar adjustments, is working, but the vertical lumbar adjustment, controlled by the pressing the upward - and downward - pointing switches on the switch, isn't responding. I hear a sound when pressing either the upward - or the downward - pointing arrow on the switch, and I can feel a faint tapping on my back through the seat, but no real movement. The other lumbar adjustment, activated by pressing the forward- and rearward-pointing switches, is working. Any ideas on this? Thanks.

Cloud9...68

Progress! After taking the middle switch apart and re-assembling about a half dozen times, I finally got it put together correctly. I found that removing the removable white cross-bar that holds two of the springs, and holding it in position with the springs pressing down on the little *****, and then inserting the rest of the switch top, I was able to snap it together without the little ***** slipping out of position. All four of the middle switch's functions now work! So I'm now the proud owner of a 10-way power driver's seat (and hopefully somebody else will be soon, as I'm planning to sell it).

But I have one remaining problem - I can tell the rear-most switch, which controls the lumbar adjustments, is working, but the vertical lumbar adjustment, controlled by the pressing the upward - and downward - pointing switches on the switch, isn't responding. I hear a sound when pressing either the upward - or the downward - pointing arrow on the switch, and I can feel a faint tapping on my back through the seat, but no real movement. The other lumbar adjustment, activated by pressing the forward- and rearward-pointing switches, is working. Any ideas on this? Thanks.

Cloud9...68

As a follow-up to my last question, does anybody know what the two-prong connector in the picture below is for? It plugs into a connector on the drivers seat, and I'm wondering if could have something to do with why my horizontal lumbar control doesn't appear to be working. I've figured out which pins are controlled by which switches on the 6-pin connector, allowing me to test the function of these switches with the seat out of the car (they all now work!), but I'm not sure how to connect the 2-pin connector to a source of voltage to allow me to test it. Thanks.

Attachment 601475

treywood

The two prong connector is the seat belt indicator connection.