Anybody know Saabs?

48builder · December 26, 2007, 12:50:29 PM

So I got these great Saab seats from a 9-3 Convertible. I'm all set to get them in the car, but I can't get them to work. Here's the problem.

The seats have a control module in them. This module has as an input a signal from the "I-bus". This signal tells the seat module that either the key is turned on or that the door is open. That signal is required for the seats to work. I traded a dozen donuts for the wiring diagrams at the dealer. It's amazing what a dozen donuts will do. The service manager has been very helpful, but he can't tell me how to bypass this signal. I know I can just cut into the harness on the other side of the module, but I would like to avoid that. If I can get the module to work I can take advantage of the memory function of the seats.

I was hoping that the I-bus signal was simply a 12V signal, but I guess it is a 8-byte computer signal of some sort.

I thought about getting the module that sends the I-bus signal, but I guess that is all tied in to the door switches, body computer, etc.

Any thoughts?

Walt

Dave · December 26, 2007, 05:17:00 PM

Quote from: "48builder"So I got these great Saab seats from a 9-3 Convertible. I'm all set to get them in the car, but I can't get them to work. Here's the problem.

The seats have a control module in them. This module has as an input a signal from the "I-bus". This signal tells the seat module that either the key is turned on or that the door is open. That signal is required for the seats to work. I traded a dozen donuts for the wiring diagrams at the dealer. It's amazing what a dozen donuts will do. The service manager has been very helpful, but he can't tell me how to bypass this signal. I know I can just cut into the harness on the other side of the module, but I would like to avoid that. If I can get the module to work I can take advantage of the memory function of the seats.

I was hoping that the I-bus signal was simply a 12V signal, but I guess it is a 8-byte computer signal of some sort.

I thought about getting the module that sends the I-bus signal, but I guess that is all tied in to the door switches, body computer, etc.

Any thoughts?
Walt

I guess id have to see the schematic.. From what your saying it doesnt tell you what input voltage it had correct? I would assume its 12v but then when u assume..

This new stuff is way hitech and it can come back to haunt you. Especially when you think its just a power seat and dc runs it.. Ya ok what voltage dc..
Dave

48builder · December 27, 2007, 12:12:30 PM

[quote="jusjunk
I guess id have to see the schematic.. From what your saying it doesnt tell you what input voltage it had correct? I would assume its 12v but then when u assume..

[/quote]

Here is some information. I wish I could find the schematic for the control module (357Dk). It appears that the Information-bus (pin 39) just tells the control module that it is OK to send voltage to the switch module (357D). So, I am going to try connecting 30 amps to pin 54 and 10 amps to connector J163 so that there will be power to the switches. That in turn will send power back to the control module and hopefully out to the motors.

Walt

http://farm3.static.flickr.com/2271/2139092483_67945fb7dd.jpg?v=0

http://farm3.static.flickr.com/2073/2139092513_117e4d22d2.jpg?v=0

http://farm3.static.flickr.com/2075/2139874734_187524219b.jpg?v=0

http://farm3.static.flickr.com/2328/2139874808_058609232f.jpg?v=0

unklian · December 27, 2007, 12:20:09 PM

Rube Goldberg would be proud.

I'd be wiring straight to the motors.

48builder · December 27, 2007, 12:25:41 PM

[quote="unklian
I'd be wiring straight to the motors.

[/quote]

Yeah, that may be what I do. Trouble is, I don't want to run 30 amps through the switches, so I'd have to use some relays for the power to the motors. I'm hoping that all the I-bus input does is allow power to go out to the switch module, and then all will be right with the world. I assume that the 30 amps the motors need is always available.

Walt

Jbird · December 27, 2007, 12:32:22 PM

Sounds like a Saab sob story, boo hoo hoo. I've always wanted to say that. Some of the body control stuff gets more complex than the powertrain control stuff. I was checking out the seat controls on my 98 Eldorado and decided I didn't have enough brain capacity left to even try to decipher them. Jbird

Dave · December 27, 2007, 03:55:48 PM

Quote from: "48builder"[quote="unklian
I'd be wiring straight to the motors.

Yeah, that may be what I do. Trouble is, I don't want to run 30 amps through the switches, so I'd have to use some relays for the power to the motors. I'm hoping that all the I-bus input does is allow power to go out to the switch module, and then all will be right with the world. I assume that the 30 amps the motors need is always available.

Walt[/quote]

Well good luck walt.. I didnt have time to go thru all the stuff you posted but i think you got a (maybe small) handle on it.. I was out most of the day today and im just getting the house and ive got chores to do since sue isnt gonna be back till sunday or monday and im leaving at noon tomorrow..
Dave

Pep · December 27, 2007, 05:22:06 PM

In all this type of stuff there is inevitably a sensor that sends a position inicator back to the control unit. That can be a set voltage, resistance or a data bite ( 8 bit word ) The control unit will store this a a pre set and when instructed, will command the seat to return to that state. To by pass that or over ride it should be possible. By isolating just the motor feed ( I'd guess the wires would be of a heavier guage than the rest ), you should be able to drive the motors direct. I'd use a relay(s) as suggested, but you will need have two for each function, as the motor will need to operate in both directions. The only way to do that is reversing the polarity. A suitable switch will need to be installed as well, that is centre momentary, 2 pole unit.

wayne petty · January 03, 2008, 12:41:08 AM

thats simple... 2 relays per motor....

each relay will use all 5 wires...

85 and 56 are control circut.. one side grounded...

pin 30 to the one side of the motor....

pin 87a to ground... the center terminal ...Normaly Closed contact

pin 87 to b + ...Normaly open contact.

with relays on either side of the motor ... when you activate one relay the contact causes power to flow through the motor and out through the non powered relay to ground.... this allows you to reverse the motor...
you would want to use this type of momentary switch.. on off on.. both on's momentary..
http://www.allelectronics.com/cgi-bin/item/STS-116/700/SPDT_(ON)-OFF-(ON)_MOMENTARY_FLAT_TOGGLE_SWITCH_.html

now... if you want to use a conventional seat switch.. try for one out of a 87 up fwd cad... they did not use relays ,,, and had 12 gauge wires all the way from the motor to the switch.... and were far superior to the earlier gm seat switches...

48builder · January 03, 2008, 07:28:14 AM

Quote from: "wayne petty"thats simple... 2 relays per motor....

now... if you want to use a conventional seat switch.. try for one out of a 87 up fwd cad... they did not use relays ,,, and had 12 gauge wires all the way from the motor to the switch.... and were far superior to the earlier gm seat switches...

Thanks for the info, Wayne. The relay idea is my plan, but I'll go look for one of those Caddy switches.l I'm also looking into using an on-board computer to create the I-bus input I need.

Walt