SaabCentral Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
130 Posts
Discussion Starter #1
2000 9-3 SE Vert, 90k miles. Driver's seat doesn't recline at all. You can hear an electronic 'tick' when you move the recline switch (both backwards and forwards) but no movement and no motor-whirring sounds. The seat also doesn't get hot though the heated seat switch lights up.

How would you guys/gals troubleshoot this?

1. Is it easy to switch the passenger side recline switch and/or motors--which are working fine--to the driver's side for testing?

2. Is there a common point of failure for the seat heating (pinched wiring, perhaps)?

I struck out searching just now. I did find the problem of uneven reclining but that is not my problem.
 

·
Registered
Joined
·
4,293 Posts
Check the green relay under the seat. If it gets a little loose, the seats will not move. Same thing with the connectors. There is more on this here if you do a search.


(view is from the front under the seat)

The seat heaters are a separate circuit, so the two should not be related, unless there is a bad ground or something like that. As for the light in the switch, that is a local function. The lamp comes on when the switch is pressed, and that's all.
 

·
Registered
Joined
·
130 Posts
Discussion Starter #3
which motor is the recline motor?

Thanks for the help.

I did a little troubleshooting yesterday. I switched the seat directional-powered switches (pretty easy, in fact--you can do it with the seats still in the car) from passenger to driver and vice versa. The passenger side seat's power functions are working fine. When I switched the driver's switch to the passenger side the passenger side power functions continued to work great. So that narrows it down a bit--it's not the driver's switch that's bad.

Next, I took out the driver's seat (also easy) and looked to see what I can see. I don't remember seeing that green relay but, then again, I wasn't looking for it.

Also, I wasn't sure which motor went with the recline. It looks like the motor furthest back is the most correct one. Is there a motor that's NOT under the seat (perhaps in the backrest)?

I removed the motor furthest back and attempted to manually move the backrest--theoretically it should be possible at this point. I had no luck. I did manage to look inside the transmission at the worm gear which looked to be in good condition. I was running out of time at this point to play merry-go-round with the motors to see if I could make one of the other powered functions quit working so I simply reinstalled the motor and hooked the seat back up in the car.

Surprise! The recline started working! No straining... perfect operation. But it only worked for two reclines then it was 'stuck' once again.

At this point I think that perhaps the transmission has contaminated grease or perhaps the gear/sproket connected to the transmission is binding because it could use a little lithium grease. I'm going to re-remove that motor and try again to force a manual recline to see if I can't free that transmission up a little bit. I believe the motor is fine but something else is resisting its work. Perhaps that relay may be loose but all other recline functions are working great and even the recline function gives a tick as if it's trying to work.

As for the seat heating I ran out of time to troubleshoot. I think I'll take the seat out of the car, trip the ABS light, and see if I can get a current from the main plug going to the seat when the seat heating is activated. Oh, and I'll check the fuse first.

If anyone can confirm I have the right motor that would help me out a lot.
 

·
Registered
Joined
·
130 Posts
Discussion Starter #6
Yep--that's correct. I have memory seats so the green relay is instead a relay box. And that's what's clicking. I'm going to switch the box out of my 2000 9-5 (also with memory seats) and see if that does the trick.
 

·
Registered
Joined
·
1,388 Posts
Dward said:
Yep--that's correct. I have memory seats so the green relay is instead a relay box. And that's what's clicking. I'm going to switch the box out of my 2000 9-5 (also with memory seats) and see if that does the trick.
Well with power memory seats it becomes very complicated now. See the power memory seats are very different than regular power seats. the motors in the memory versions have position sensors (potentiometers) built into each motor that tell the power seat module the position or location of the seat, this is used for the memory function to return the seat to that position. If one of these position sensors is damaged or inoperative, the entire movement by that motor will not function as the "brain" module doesn't know the position of the seat and will not allow the motor to operate. I copied this right out of the Saab WIS, workshop manual:

"Motors, position sensors (potentiometers) and switches are in their turn supplied with current via the electronic unit. The electronic unit continuously monitors the switches and when a valid combination of switches is activated it performs the corresponding function.

When the motors are operated, the electronic unit monitors the current consumption of each motor and the position of the seat via the position sensors.

The electronic unit also tests the system, Faults it discovers are stored in the form of diagnostic trouble codes which can later be retrieved by means of an ISAT.

The position sensors consist of potentiometers mounted on the shaft of each motor. A power supply of about 5 V is applied to pins 1 and 3 of these potentiometers by the electronic unit. When the motor shaft rotates, the voltage or the centre tap of the potentiometer, pin 2, normally varies between 0,4 and 4,6 V, By measuring this voltage the electronic unit can ascertain the setting of the seat,

The seat has a number of switches, one pole of which is supplied with +12 V (battery voltages from the electronic unit When a switch is activated, the 12 V supply is returned to tl corresponding switch input on the electronic unit, The voltag on the electronic unit's switch input then changes from O V t 12V,

The electronic unit continuously monitors the two sets of pushbuttons and when a valid command is detected it performs the corresponding function, i.e. it controls the motors in the case of manual operation or when a stored setting is recalled, or stores the seat setting if the M button is depressed.

When the seat is manually adjusted, the electronic unit senses which manual control switch is activated and supplier the corresponding motors with current so that they run in the appropriate direction.

The electronic unit allows only two motors to run at the same time and will stop if more than two manual control switches are activated at the same time. The electronic unit supplies these motors with current as long as the relevant manual control switch is activated (but not for longer than one minute).

The backrest has no mechanical stop to limit its rake angle either direction instead, the electronic unit determines the rake angle limits by reading the backrest position sensor. The electronic unit therefore allows no operation of the backrest motor if its position sensor is defective.
 

·
Registered
Joined
·
130 Posts
Discussion Starter #8
Well, I think you may have hit that one on the head. Probably a faulty sensor in the backrest motor.

Does the WIS say what happens when a power reset / drain occurs? How does it know to "start over"? Or is there solid state memory in the control module?
I think I'm still going to try the control module switch to see if that's not causing the problem. Unfortunately I don't have a good used Saab parts source to get that rear motor; any suggestions?
 

·
Registered
Joined
·
1,388 Posts
Dward said:
Well, I think you may have hit that one on the head. Probably a faulty sensor in the backrest motor.

Does the WIS say what happens when a power reset / drain occurs? How does it know to "start over"? Or is there solid state memory in the control module?
I think I'm still going to try the control module switch to see if that's not causing the problem. Unfortunately I don't have a good used Saab parts source to get that rear motor; any suggestions?
According to WIS the seats have a non volatile memory. I'll post the entire section here for you since you seem to be capable of fixing your seat.

----------------------------
Power Memory Seats

A memory function is offered as a factory-fitted option for the electrically adjustable driver’s seat. Three different seat settings can be stored in the memory and the seat will automatically adjust the seat when the appropriate buttons are pressed.

To provide the memory function, the ordinary electrically adjustable seat is fitted with an electronic unit, a position sensor on each motor, and a switch assembly with four pushbuttons for programming and activating the memory.

The controls for the memory and programming functions consist of four pushbuttons. Three memory buttons, "1", “2” and "3", and a memory store button "M". Seat settings are stored in the memory as follows:

  • Adjust the seat to the desired position by means of the regular setting buttons.
  • Store the setting by simultaneously pressing the "M" button and one of the memory buttons -1, 2 or 3, To activate the memory function, keep the appropriate memory button depressed until the seat has adjusted itself to the stored setting.
The electronic unit is supplied with current from the seat relay which in its turn receives a + 30 supply via a 30 A fuse.

Activation of the seat relay takes place when the ICE (Integrated Central Electronics) unit grounds it. This happens when +54 is active or when any door is open.

Motors, position sensors (potentiometers) and switches are in turn supplied with current via the electronic unit. The electronic unit continuously monitors the switches and when a valid combination of switches is activated it performs the corresponding function.

When the motors are operated, the electronic unit monitors the current consumption of each motor and the position of the seat via the position sensors.

The electronic unit also tests the system. Faults it discovers are stored in the form of diagnostic trouble codes which can later be retrieved by means of an ISAT.

The position sensors consist of potentiometers mounted on the shaft of each motor. A power supply of about 5 V is applied to pins 1 and 3 of these potentiometers by the electronic unit. When the motor shaft rotates, the voltage on the centre tap of the potentiometer, pin 2, normally varies between 0.4 and 4.6 V. By measuring this voltage the electronic unit can ascertain the setting of the seat.

The seat has a number of switches, one pole of which is supplied with +12 V (battery voltage) from the electronic unit. When a switch is activated, the 12 V supply is returned to the corresponding switch input on the electronic unit. The voltage on the electronic unit' switch input then changes from O V to 12 V.

The electronic unit continuously monitors the two sets of pushbuttons and when a valid command is detected it performs the corresponding function, i,e, it controls the motors in the case of manual operation or when a stored setting is recalled, or stores the seat settings if the M button is depressed.

Invalid commands, such as simultaneous activation of several memory buttons or simultaneous activation of more than two switches in the case of manual operation, will result in no function being performed. If a memory store command or a stored setting command is detected at the same time as a manual command, the electronic unit will carry out the manual command.

Manual adjustment of the seat

When the seat is manually adjusted, the electronic unit senses which manual control switch is activated and supplies the corresponding motors with current so that they run in the appropriate direction.

The electronic unit allows only two motors to run at the same time and will stop if more than two manual control switches are activated at the same time. The electronic unit supplies these motors with current as long as the relevant manual control switch is activated (but not for longer than one minute).

The backrest has no mechanical stop to limit its rake angle in either direction, instead, the electronic unit determines the rake angle limits by reading the backrest position sensor. The electronic unit therefore allows no operation of the backrest motor if its position sensor is defective.

Storing seat settings in the memory

When a seat setting is stored, the electronic unit reads all position sensors and stores their readings in one of the seat memories. The seat memories are non volatile and retain their information even when the electronic unit is not supplied with current.

If any position sensor is defective, no new seat setting will be stored in the seat memory but the seat setting stored earlier, if any, will be retained.

Memorized seat settings

When a memorized seat setting is recalled, the electronic unit reads all position sensors and operates the motors until the seat setting corresponds to the setting stored in the seat memory, or until the memory button is released.

If the electronic unit detects a fault in any position sensor, or if the seat moves too slowly in any direction, the corresponding motor will be stopped.

Diagnostics

Faults detected by the electronic unit are stored in the form of diagnostic trouble codes. These codes can subsequently be retrieved by connecting an ISAT to the test socket located under the dashboard next to the steering column. Using the ISAT, commands can also be given for obtaining readouts from each individual switch and all position sensors.

Internal self test

The electronic unit tests certain of its own components. If a fault is detected, a diagnostic trouble code for a control module fault is generated.

Testing of external components

All position sensors are tested when seat settings are stored in the memory and when stored seat settings are recalled. The backrest position sensor is also tested when the backrest is adjusted by means of the manual control switches. If a position sensor is defective, it will only be possible to operate the corresponding motor manually (exception: the backrest motor cannot be operated if its position sensor is defective) and it will not I possible to store any new seat setting in the memory.

The relevant motors are tested for high current consumption when they are operated by means of the manual control switches or when a setting stored in the memory is recalled. If current consumption is too high, the motor will be stopped, if the electronic unit detects exceptionally high current consumption in any motor four times in succession, it will no permit any more attempts to start it. Fault diagnosis must be carried out and the diagnostic trouble code cleared before it will be possible to operate the motor again.

Principle of operation

The front seats of the car can be adjusted by means of switches on the outside of each seat. Electric motors move the seat in a fore-and-aft direction, change the height of the seat cushion at front and rear, and change the backrest rake angle.

When the ignition switch is in the Drive position and/or when any door is open, switch 357 on the drivers seat is supplied with power via fuse 16, Switch 358 on the front passenger’s seat is supplied with power via fuse 5. Switch 357 (driver’s seat) controls the following electric motors:

• Electric motor 357A moves the seat in a fore-and-aft direction.
• Electric motor 357B raises and lowers the front of the seat.
• Electric motor 357C raises and lowers the rear of the seat.
• Electric motor 357D changes the backrest rake angle. Switch 358 and electric motor 358A-D are used to control and move the front passenger’s seat in the same manner.
 

·
Registered
Joined
·
130 Posts
Discussion Starter #10
Sonofabiscuit that's complex.

So it sounds like switching the control unit will have no effect if the recline sensor is still faulty. Quickly cruising thesaabsite I don't see where you can buy a sensor. Since it's internal to the motor I assume it would be difficult to replace it, anyway. Man, I hate the crapshoot that is used parts when it comes to electricals.

Thanks for your WISdom.
 

·
Registered
Joined
·
1,388 Posts
Dward said:
So it sounds like switching the control unit will have no effect if the recline sensor is still faulty.
Correct.
Dward said:
Quickly cruising thesaabsite I don't see where you can buy a sensor. Since it's internal to the motor I assume it would be difficult to replace it, anyway.
According to EPC, the sensor is not sold as a separate part, you have to buy the motor unit complete with the sensor already attached. The original Saab P/N is 44 76 107.

Sometimes you can find these motors on eeebay for about $30 or so $. When you look at the motor the position sensor is actually located on the exterior of the motor, at the top on the output shaft. So it is easy to replace just the sensor, but since its not a part that is sold separately, you see where I'm going with this.
 

·
Registered
Joined
·
4,293 Posts
Diosnoche said:
According to EPC, the sensor is not sold as a separate part, you have to buy the motor unit complete with the sensor already attached. The original Saab P/N is 44 76 107.
I think that may be the p/n for the NG900, but not the 9-3 (?)

Diosnoche said:
Sometimes you can find these motors on eeebay for about $30 or so $. When you look at the motor the position sensor is actually located on the exterior of the motor, at the top on the output shaft. So it is easy to replace just the sensor, but since its not a part that is sold separately, you see where I'm going with this.
If I am looking at the diagrams correctly, then the NG900 has a couple motors with separate sensors labeled "potentiometer", and a couple motors where the sensor is part of the unit.

The 9-3 seems not to have anything labeled a separate sensor, but someone would have to confirm that. In any case, I would guess that you could test the resistance, IF it is a potentiometer. The recline motors could be swapped between the passenger and driver seats.

Replacing it with a used motor would probably be simpler.
 

·
Registered
Joined
·
130 Posts
Discussion Starter #13
If I could find a used motor that would be nice. The places I've called on car-part.com have seats but aren't willing to part the seats. No pull-a-part or similar places around here--at least not that have Saabs. I'm striking out on eBay, even.I'll try 'stealing' the passenger seat recline motor as a temporary fix. It's raining solid until 8p so it won't happen today.
 

·
Registered
Joined
·
157 Posts
My 900 (96 SE convertible) doesn't seem to have a relay on the driver's side, only the passenger's. My seats work only intermitently and with no consistent thread other than the longer I drive the car, the more likely the seats are to return to operation. Could this be a power on the harness problem or maybe even an alternator problem (I know it's not the battery as I replaced it following this line of reasoning). Any ideas?
 
1 - 14 of 14 Posts
Top