Testing front seat out of car

[buildit]

Does anyone know how to connect power to the front seats in order to test them out of the car?

In this seat repair video at https://youtu.be/Av_Bfcz-wH4?t=263 an adapter cable connected to a 12 v power supply is used.

I havnt been able to locate a wiring diagram to reproduce that cable.

[petejk]

Try looking the seat wiring connectors up in these PDFs.
I ran them through Adobe OCR so they are keyword searchable.

Electrical Troubleshooting Manual:

https://1drv.ms/b/s!AjQciiq98CMJoaNq...20SdA?e=HUXQ4X

Electrical Troubleshooting and Diagnosis:

https://1drv.ms/b/s!AjQciiq98CMJoaN6...nQzIA?e=waBdwD


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[buildit]

Thank you!

Sent from my ONEPLUS A6013 using Tapatalk

[01BMWs]

anyone else having trouble with these links?

[Timm]

If you are having problems I have them all on my pages - left-hand pane: https://www.meeknet.co.uk/e31/

[01BMWs]

Thanks Timm !! I just found your site after my recent purchase of a '91 850i. I've been doing more researching and reading than doing at this point......but I have the passenger seat out and it has the up/down problem. Driver's has the up/down and forward/back. Should I take care of all the cable sheaths whilst the seats are out of the car as a solution and a preventative measure?

[Timm]

It certainly makes it a darn sight easier out of the car!

[01BMWs]

I got the fix on the passenger side, but the drivers side is giving me fits.

Heading to body shop soon for repairs/paint and then I'll get back to the drivers seat......cuz now I can't fit in to drive it!

[mutley999]

Sorry to jump in on here but:
My drivers seat (UK) is very slow moving backward or forward It works OK in all other directions just backford or foward, so just wondering anyone had this problem and what was the fix?
Thanks

[Hyper]

...connect power to the front seats in order to test them out of the car?...

Very useful idea.
Not only helps to diagnose known Inops, but needed to verify that everything is fixed and correct before lifting that 85lbs seat back into the vehicle.

Headzup ETM, there are many flavors of electrical, due to both model years and feature/trim options.
Having both an impressive engineering degree on the wall AND a basic VOM in my hand, I'm able to report that the situation is excruciating simple.

Basically, applying only power (thick brown w/red) and ground (thick brown) to the main switch panel, you then gain control of the big motors.
The switch panel is quite dumb, meaning no electronics, and it is also electrically isolated from the frame/body.
It's only brilliance is in knowing how to reverse power and ground to the motors in order to reverse the seat motions.
If YOU just happen to reverse the power & ground to the harness, no harm done but the seat motions will get logically reversed.
(However, any additional work on sensors, etc, depend the ground wire being at ground/lower potential.)

At the body floor harness, the connector and pins STYLES were not US Amp style, so my pin extraction tool did not work.
This perfectionist would then have temporarily stuffed the pins into a 2-pos housing.
However, the pin DIAMETER (thickness) did match, so I merely connected up a pair of loose 0.093 female pins, isolating them with shrink tube.



That bench supply is limited at 5 amps and I set the voltage to, uh, 12 volts.
Display panel says: A motor typically has a no-load steady-state of just under 2 amps.
In-rush is around 3 amps, stall is around 5 amps.

As for all those other wires to/from body...
* Sensor switches: Seat back, seat belt, passenger weight (y/n?)
* Heater option, with switch on console.
* Memory option, on drivers
* All your other options: sport seat thigh support.

[Hyper]

Well, that works for the dumb passenger side, and also for a basic trim driver's,
but fails when you have memory trim and therefore a computer is in the loop.
The icon panel no longer drives the motors directly, but feeds into the seat control box where occupant input gets merged with memory input before going out to the motors.

With only power applied, as before, the box signals its dissatisfaction by doing nothing except blink the "M".
I'll guess that among other trifles, it wants to contact the body module.
Yes, we could achieve motion by plugging our supply directly into each motor, but a higher goal is to verify overall system integrity.
So we real DO need to have in the loop, the control box and feedback sensors.