How to operate power seat outside car?

[Simracer]

Hi there.

I am currently building a racing cockpit at home and bought a passenger power seat from a 2001(?) 9-5.

We're trying to figure out how to get the controls to work to adjust the seat via 12V/12A coming from a battery charger with a lighter plug on its back. Will that work? We found someone that had measured the motors to use up to 7A, so that should be low enough to work with the 12A plug.


We disconnected the airbag by cutting the yellow cable hose so that should be out of harm's way.


We tried plugging in the main current and ground, but of course nothing happened.


Can some of you Saab wizards guide us in the right direction to make this comfy seat work indoors?
Preferably with pictures and/or clear instructions... We were scratching our heads there, but figure we have to put some more grounds in, and maybe current to some more slots 

We're at a loss here!

[sgould]

Welcome!

According to the wiring diagram, the switch on the passenger seat only requires a live and earth.  But that is directly at the switch.  The relay that controls it is also in the seat.

When in a Saab, the relay is fed 12v to both sides, the powered side goes to the seat switch and switched side is earthed through the "TWICE" unit, which is the logic bit that does some yes/no safety stuff.  But as far as the seat is concerned, it does this by providing the earthing point, or not.

Attached is the wiring for the seat from the switch on the side of the seat.  Second one is a detail of the relay.  Third is a full overview which is too small to read, but gives the layout.

Item 632 is the TWICE unit that earths the control side of the relay.

Connector H29-1 is the main block for the whole seat that connects to the loom in the car.

[sgould]

If you are working from the main connector, to get the seat to work, you need to power the red wire at pin one; earth pin 2 which is the seat earth (black wire), and also earth pin 29, which is the green/yellow wire and earths the controlling relay.

Ignore the red/blue wire.  That cross connects to the driver's seat. But will have 12v on it when the relay switches on.

[Simracer]

If you are working from the main connector, to get the seat to work, you need to power the red wire at pin one; earth pin 2 which is the seat earth (black wire), and also earth pin 29, which is the green/yellow wire and earths the controlling relay.

Ignore the red/blue wire.  That cross connects to the driver's seat. But will have 12v on it when the relay switches on.

Wow, sweet! Thanks for the help, much appreciated!


So to make this fool proof for us, all we have to do is:

Give 12V/12A to the main red wire (pin 1)

Ground main black wire (pin 2)

Ground green/yellow (pin 29)


Will my new charger with cig plug be enough to drive the motors while sitting in it? As stated it gives a maximum output of 12 ampere; and the unit is protected from short circuits, over ampage and such so it shouldn't burst into flames if it's too much...

[sgould]

Those three wires seem to be all that's needed.


I think the 12A supply may be marginal at best. 

In the Saab, Fuse 11 is rated at 30 amps.  It only controls the passenger seat, the central locking and the sat nav.  Central locking and seat are unlikely to operate at the same time and the sat nav takes a minimal current, so the rest must be for the passenger seat.

It might be rated at 30 amps to allow for raising the seat and tilting the back at the same time, but I can't say for sure.  I think you may have to fuse it for your charger and see if the fuse blows or the charger trips out.  Maybe try one motor at a time and measure the current.

[Simracer]

The charger has a real time amp meter, so we'll find out immediately if there's too much power needed

I won't have access to the garage until Monday, so I'll get back to ya with the results...
Very promising though, and if the charger is too weak, we'll just put in an mc battery instead.

[Simracer]

And right you are, my very much appreciated helper!
Went back to the garage today, hooked up the charger via the 12V cig plug to the main red, main black and earthed the green/yellow wire.

Worked like a charm!

For future reference I can tell you that the live metering told us the motors for the seat pull between 4.3 A down and 6.1 ampere up. At the ends it pulls 15.6 ampere briefly, which is apparently OK for this charger. When we mount it and sit on the seat we'll get back and update the numbers with weight on the seat. When you use two motors at the same time, the amps simply double; so if anyone is looking for this solution later on - be sure to only use one motion at a time to ease the pressure of your charger.

THANK YOU for your help, couldn't have done it without you! Much much appreciated!

[sgould]

Well done!