seat directlonal connection or switch. 2 issues '81 911

[jgurnari]

first issue:

Using the switch, Upper seat back tilts backward but does not tilt forward.

Troubleshooting:

Power is going TO the connector (blue circle) from power under the seat.
Only 1 wire on the opposite side of that connector gets power. The back will tilt backward. When I swap the 2 wires (grey and black) from one side of the connector to the other, the back will tilt forward. reversed. Which tells me its not the motor.

Second issue:

only one side of the seat back tilts, again in one direction and wont reverse unless I swap the grey and black wires in the connectors, and when it tilts, only one side moves, meaning it contorts / twists to one side.

[john walker's workshop]

Switch. Typical issue. Some folks get lucky cleaning them with contact cleaner. I usually get smoke.

[jgurnari]

im going to attempt cleaning it

[PopsRacer]

You can try shooting some DeOxit in there. I had no luck with that myself and had to replace the switch. I doubt you need any tech help w/this but if extra pics are any help I took a bunch: https://www.joepampel.com/post/adventures-in-power-seating

[76FJ55]

I've had good success with spraying DeOxit into seat switches in the past, so I do think that is a valid place to start. I actually drilled a very small hole in the switch body to allow the spray good access to the switch contacts.

The seat back should be driven by 2 cables (items 7 and 8) that com down off the motor (item 4) located up in the head rest area of the seat back. I would try to determine if one of those cables has failed or come disconnected. Below is an image from the parts catalog for a power seat back.

FYI, 81 would not have had power seats from the factory, so yours has been retrofit with seats from a later car. Power seats were not available in the 911 until 1985.

[jgurnari]

could the cause of my seat contorting and twisting on the left due to this cable not being connected from the motor or whatever at the hinge?...only one side tilts.

Im I correct that there are 2 of those rotating cables from that motor to each hinge?



[QUOTE=76FJ55;12406603]I've had good success with spraying DeOxit into seat switches in the past, so I do think that is a valid place to start. I actually drilled a very small hole in the switch body to allow the spray good access to the switch contacts.

The seat back should be driven by 2 cables (items 7 and 8) that com down off the motor (item 4) located up in the head rest area of the seat back. I would try to determine if one of those cables has failed or come disconnected. Below is an image from the parts catalog for a power seat back.

FYI, 81 would not have had power seats from the factory, so yours has been retrofit with seats from a later car. Power seats were not available in the 911 until 1985.

[76FJ55]

Yes, there should be a total of two cables connected to the recline motor. one runs to the right seat base hinge and one runs to the left seat base hinge. if one of these is disconnected then only one side of the seat will move and the other side will bind. these is a gearbox (Items 4 and 5)on each side that the cables connect to with a worm gear output that drives the seat back forward or back.

[76FJ55]

[A930Rocket]

Has anyone stripped the leather off and replaced the seat back motor themselves? How difficult was it?

I’ve replaced my switch and I have power at the connector, to the seat back motor, but nothing moves and I don’t hear anything.

[jgurnari]

i get nothing from one tilt switch. are there 2 actuated cables for each side of the seat motor?

Originally Posted by A930Rocket

Has anyone stripped the leather off and replaced the seat back motor themselves? How difficult was it?

I’ve replaced my switch and I have power at the connector, to the seat back motor, but nothing moves and I don’t hear anything.

[76FJ55]

Originally Posted by jgurnari

i get nothing from one tilt switch. are there 2 actuated cables for each side of the seat motor?

not quite sure I understand what you mean by this? when you say "tilt" are you referring to the lean back tilt?

you have 2 switches one that is four way (up, down, forward and aft) and one that is two way (up and down). The forward and aft on the four way should activate the recline motor (Item 4 in first pic, located near the head rest of the seat back and running two cables one at each recline gearbox (items 4 and 5 of second pic) to adjust the angle of the back of the seat.

The up/down movement of the switches (both 2 and 4 way) should raise and lower the the seat base (front switch effecting the front of the seat base and rear effecting rear). these are attached to the seat base motors (Items 12 and 12B in the second picture), which correspondingly have drive cables to the four seat base lift gear boxes (Items 4 and 5 (two each) of the second pic).

Image 1.


Image 2.

[76FJ55]

Originally Posted by A930Rocket

Has anyone stripped the leather off and replaced the seat back motor themselves? How difficult was it?

I’ve replaced my switch and I have power at the connector, to the seat back motor, but nothing moves and I don’t hear anything.

Have you tried using a separate source to power the seat back motor?

when you were checking voltage what were you Using for ground? the switch has to reverse both positive and ground current paths, so if you were going direct to chassis for ground you may only have one set of contacts in the switch working and may not have a complete circuit. also if using a digital volt meter it there is high resistance through a switch contact the DVM has extremely low current draw so may show voltage even when the switch has little to no current carrying capacity. if you have an incandescent test light, put it across the leads that come from the switch and see if it will light with the switch pushed in both directions.

[jgurnari]

first, when i say tilt, I am referring to the backrest upper seat tilt forward and back, not the bottom seat cushion up and down.

this is my previous post on power 1st post on thread:

"Power is going TO the connector (blue circle) from power under the seat.
Only 1 wire on the opposite side of that connector gets power. The back will tilt backward. When I swap the 2 wires (grey and black) from one side of the connector to the other, the back will tilt forward. reversed. Which tells me its not the motor.

Second issue:

only one side of the seat back tilts, again in one direction and wont reverse unless I swap the grey and black wires in the connectors, and when it tilts, only one side moves, meaning it contorts / twists to one side." END QUOTE

But I see only right side stub axle moving. Thats why I was wondered if there were 2 separate coil cables coming from the headrest motor to move the hinge on both sides. but obviously there are 2 (pic1)

You mentioned motor 4 and 5 in PIC 2....those are the motors under the seat for the bottom cushion that lift the seat up and down. Are you saying that the cable ends in PIC 1 from headrest motor in backrest connect to the motors under the seat as well. If not where do the cable ends connect to, to move the hinges to tilt the upper backrest?
Maybe one cable is out of place and thats why only one side is not responding. Hope that was clear! thanks

Originally Posted by 76FJ55

Have you tried using a separate source to power the seat back motor?

when you were checking voltage what were you Using for ground? the switch has to reverse both positive and ground current paths, so if you were going direct to chassis for ground you may only have one set of contacts in the switch working and may not have a complete circuit. also if using a digital volt meter it there is high resistance through a switch contact the DVM has extremely low current draw so may show voltage even when the switch has little to no current carrying capacity. if you have an incandescent test light, put it across the leads that come from the switch and see if it will light with the switch pushed in both directions.

[A930Rocket]

^^^ I was using a test light with the ground side clipped on the door limiter, after I replaced the switch with a new one. I can’t remember if I was getting power out of both wires at the connector, but at least one.

[jgurnari]

do you know where those ends from the motor go to PIC 1? Do the share the lifters under the seat that lift the bottom seat up and down?...I dont see the cables coming out of the bottom of the backrest so the cant share those lifts under the seat...

[76FJ55]

I think they attach to a gearbox built into the seat back (circled in red). these boxes drive the square shaft which extends out into the recline mechanism/arm of the seat base.

take a look at this thread maybe it will offer some ideas. having only one side recline looks like it could be a failed square drive rod.

https://rennlist.com/forums/928-forum/1273176-s4-seatback-recline-mechanism-issue.html

[jgurnari]

Thanks 76FJ55
I found that the cable was out of place and the motor is working. Now I hope that my issue is the seat switch...been through everything else.

[76FJ55]

Originally Posted by jgurnari

Thanks 76FJ55
I found that the cable was out of place and the motor is working. Now I hope that my issue is the seat switch...been through everything else.

try putting power directly to the lead going to the motor and grounding the other pin. the motor should one in one direction either reclining or moving the beat back forward, then revers the power and ground pins and it should go the other way. this will confirm the motor and the drive system on the seat. if that doesn't give good results you should figure out why before going back to diagnose the switch.

[jgurnari]

got to be the switch..new one on its way

[A930Rocket]

Not to hijack the thread, but is there a way to manually adjust the seat back? Either from the outside or from the inside, turning the squares?