9-5 Door mirrors not moving

[sgould]

First thing I’ll try today is shorting across the door switch and see if there’s any movement.  I’m not optimistic, because the mirrors still don’t move with the memory seats.  The switch can’t have any part in that, surely? The resting position of the switch is with no contact made by any of the plungers.  But I’ll study the diagram again!

[sgould]

Oh! ………

I can’t do electrics in the rain

[sgould]

Still raining.  It should be clear by 4.00pm...

In the meantime, i've been trying to understand the wiring diagram, and I think it's wrong.

If you have wiring diagram in WIS and look at the door switch.  The 12v power comes in at pin2.  Earth is pin 1.

If you look at the drivers side mirror (680D) and make the connection with switch 125 to the right.   Pins 4 and 5 are shown connected together inside the switch, but 5 is the common feed, via pin 2 on the mirror, to both the horizontal and vertical motors and pin 4 on the switch connects, via pin 4 on the mirror to the opposite side of the horizontal mirror, which means there is no voltage difference to drive the motor...

Same wiring to the passenger side,

[sgould]

It might stop raining in half an hour!

A desktop session here might have brought a way forward.

Further consideration of the wiring diagram convinces me that as the only wires powering the mirror motors go via pins 4, 5, 7 (& on the door switch.  These pins should go live when the memory seat buttons are pressed.  If they don't then either the PMM is faulty, or the wires between are broken.  I'm loth to break the door hinge connectors as there are airbag sensors in the door, and I need the ignition on to test the circuit. I don't want any issues with the airbag lights, although I have a Tech2 and can reset it.  Maybe just leave everything off when I split them and spray them and then test at the door switch connector again.

[sgould]

I think that my idea that the wiring diagram is wrong is in correct!    Putting 12v to both sides of the motor stops it working.  So only one of the two motors work, which is what you want when you press the up/down/left/right button  Doh!!!
 

[carrera]

I sort of understand, but remain confused 

Where I got to was as follows, for the drivers side:

Motors have connection to the switch, two connections per terminal
Power is supplied by either physical movement of the switch closing a set of contacts, OR
Direct from the PMM module,because of seat switches

I have no idea how the PMM module / seat switches know the position of the mirror motors..... but haven't looked properly either

You should be able to see 12v at pin 2, 4 or 5 without removing the connectors

Interesting you see pin 5 as a common feed. It is, but I come from a common earth mentality. Makes little difference in this case, apart from testing

Oh, and if you disconnect the door connector with the ignition off, how does the door sensor know that you ever switched the ignition on (if a code is thrown you can clear it anyway I assume)

[sgould]

Well, testing will be tomorrow.  My work outside went the way of the test match at Lords.

The middle common connection can be live or earth, depending on which way the switches send the current to change the direction the motor moves.

There are seven pins to the mirror motor.  Three are the power to the motor.  The other four connect to the horizontal and vertical sensors, I think.  So the motors move in the direction you want, and as far as you want.  But when moved by the seats, the sensors control the stop position of the motor.  And also the direction of the current.  The logic must be in the PMM.

The only way that the seat switch can move the mirror is by power to the pins with two wires.  If the door switch is at rest, none of the contacts are being made, so no current flows through the switch.

If the door connector is disconnected and the ignition turned on, the airbag crash sensor oin the door won't be found by the SRS control box and throw an error.

[carrera]

That all makes perfect sense

Good idea splitting this topic off, seems like it will be turning into a reference thread 

[sgould]

The right hand door mirror is adjusted quite a long way to the right.  I will try and move it to the correct position by hand.  It occurred to me, that if it is at full travel, one of the position sensors may be unable to make a plausible reading and it’s inhibiting the whole system.

[sgould]

A bit more playing this morning.

If I put a meter across any of the four pins that I have decided sense the mirror position, the resistance changes when I move the mirror.  To measure this, I have the mirror disconnected, so no power there to confuse things.  So I would think that this confirms my view that they are the position sensors. And the are still working.

When I check the voltage at the door connector.  There are a lot of small mV readings, which I assume are spurious, and nothing changes when I move the seats.  So I'm concluding that the PMM unit is faulty as the power comes through there.  But that doesn't explain why the mirrors fail to move with the door switch.  The power and earth to the door switch are separate, and I get 12v at the switch and the earth continuity is good.

So now I'm quite confused.  It seems that both the PMM and the door switch have failed, at what seems to be the same time.

More checks needed, I think.  I will check Tech2 to see if the seats are sending any I-Bus to the PMM and have a hard look at the door switch again.

[phoenix]

There's a good description of the PMM signals to the motors in WIS, have you seen that?

[sgould]

Yes, I found all the test values, and I have a suitable meter, so it looks like a slow plod through.  I was hoping for a general failure, but it looks like I'll be tied up for a while.  I'll have to cut the ties to the loom so that I can get at the connector more easily. 

I'll try and find the same info in SaabWIS online.  It will make life easier. My full WIS is on a Dell and the screen hinge has broken and it's all floppy!

[sgould]

Success!!

I'm not quite sure how it all works.  I thought that I had worked it out

I was certain that there is no direct connection between the switch operation anb the memory seat operation.  But...

First off I disassembled the door switch, and found that the contacts were dirty/corroded.  The contact cleaner and some cotton buds wouldn't fix it, so I had a quick brush over with my fibreglass cleaning pen and they came clean.  Then a quick wipe with the contact cleaner and reassembled.   A quick test with the meter found voltage on the pins where there wasn't any before.  So I reconnected, and the mirrors worked!

Then I checked the seats and the mirrors moved with the memory    I know not why.  I will take another look at the wiring diagram but it's not self-evident.

Tomorrow will be the reassembly of all the trim and glovebox...

[phoenix]

Well done!

[carrera]

Same failure mode as mine then

Glad you got it sorted, that switch wiring & how it works still seems to be a bit of a mystery