westija

Hope everyone is enjoying the weekend

Trying to figure out what is the cause of the problem with my '89 S4 door locking motors not working. The fuse # 1 in front of the CE is fine. I do not know if there is a relay to the door lock (my cheat sheet does not indicate any)

As neither driver's nor passenger's side are locking the other side when locking with key (outside) or paw or posts (inside), I believe I have a power issue. I cannot hear any electrical motors working either.

IF ALL DOORS ARE UNLOCKED - From outside or inside with key at "0" or "1", when I lock one door, it locks itself, it does not do anything with the other door, it activates the red LED on both doors. Then I can unlock it, it will again not do anything with the other door, it will deactivate the red LED lights.

IF ALL DOORS ARE LOCKED - with key at "0" or "1", when I unlock one door, it does not unlock the other, it does not turn the red LED light off (remains ON), but I can hear a "click" at the Central Locking Unit.

With the key at ignition at "2": if all doors are unlocked and I lock one of them, it does not locks the other door, the red LED lights come on and now the Central Locking Button comes ON too. If all doors are locked, when unlocking one door, it does not do anything with the other but the Central Locking Button turns off and I hear the click again.

Everytime I push the Central Door Locking Button when it is ON, I can hear a click and a buzz at the CL Unit but it does not unlocks the doors.

Since I have the driver's door panel removed due to another issue (window motor) I tested the 5-wire connector that leads to the motor area (driver's side) and tested I its wires as follows:
Brown: grounded
Green / White: 12V
Yellow / Blue: nothing (?)
Green / Red: ground
Blue + White: ground

I also tested continuity of all these 5 wires (driver's side) from the motor to the connector inside the passenger compartment above driver's left knee. All checked OK.

Looking at the electrical schematic I think I should have continuity between the BL/YE wire from motor to the Central Locking (CL) Unit terminal 11 and I do NOT.
I do have continuity between GN /RE wire at the motor and CL terminal 4; BL / WH wire at the motor and CL terminal 2; GR / WH wire at motor and CL terminal 10.

Need some help:
1. On this '89 car are there two inline fuses behind the CE (as per some threads)?
2. Should I have continuity between the BL / YE wire and the Central Locking Unit terminal 11 ?
3. Is there a Relay involved and can I swap it with some other to test it?

Any other idea?

Many thanks

westija

Hi folks.
I'm still struggling here, but found a couple of things that I hope will trigger some suggestions.

If I disconnect the wires to the Driver's door lock motor - As I have the key on the ignition on position 2 and lock both doors, the red button light on the central console comes on. When I manually unlock the PASSENGER's door, the console red button bulb turns OFF (it is still not unlocking the other door). However, if I have both doors locked and unlock the DRIVER's door, the console red button bulb stays ON. (all these with the driver's door motor wires disconnected)

I do have the Driver's Door panel out (and therefore the mirrror control, countesy light and jamb light removed) and have the Central Console out (so all windows switches, stereo , A/C control were removed). I connected the stripe that has the red button and the odometer zero button. I don't think the fact that I have the switches and lights out causes any issues with the door locking.

Finally I checked behind the CE and my car does not have the two inline fuses.

Please let me know if you have any ideas and if there is a relay involved that I need to test somehow.

Thanks
Jose

MainePorsche

I had an interesting finding with my door locks.
Both doors functioned normally from the central button.
Both doors functioned normally when locking/unlocking with the passenger door key.
With the driver's key only the motor on the Driver's door worked. Nothing with the passenger door.

My 87 has 4 wires at the motor pigtail, same as pg 57-22 in the WSM.
I had NO voltage at the harness on any combinations.
My red/white was power in.
My green/white and yellow should have alternated with voltage depending on whether locked or unlocked. These wires made union with the other motor.

I tell you this for I note your connections between the motors (BL/YE at pin 3 of the Control Unit Central Locks, GN/RE at pin 4, BL/WT at pin 2) have no voltage.

With the findings on my pigtail I concluded a wiring issue. I dissected the driver door harness at the stress point and behold my BROWN was severed. Repaired and now all works as should (also repaired some wires that were on their way out).

Your voltages at the intra -motor wires should read something when locked/unlocked if they're intact.
Look at my situation - I had nearly normal function with a severed ground to driver motor, and no voltage anywhere at the pigtail.

Go with the horse not the zebra. Check the wires at the stress point (driver's side first).
Hope this is some help.

westija

MainePorsche, thanks for the tip.

I re-did my continuity tests at the Driver's Door central lock harness and found I was picking the wrong terminal at the Central Lock Control Unit for the Blue/Yellow wire.
It is supposed to connect to the CL unit at terminal 3 (not 11). I tested it and found it is fine. I also double checked the other 4 wires and they are fine too. So I am assuming I am fine at the Driver's side (I hope?)

On the Passenger side, I tested from the terminal above the glove box to the Central Lock unit and all 5 wires related to the lock tested fine. I have not yet opened the passenger door panels to check in there. Because I want to check on the forum for help with one last thing before I do: I suspect of the connector between the door lock button at the console and the rest of the wiring.

As I read the diagram I have (thank you Kalspeed) I don't think I am supposed to have wires connected to terminal 1 (please see picture).


I have a RED wire coming from the console button connecting to a BROWN/WHITE on the other side. These have 12V on them and TYPICALLY a BROWN/WHITE wire is a switched ground, isn't it? So, I suspect the PO made some changes here.

Set up I found: (Terminal number - wire from Console Button - connecting to wire to the rest of the car)
6 - Gray wire connecting to Brown wire - OK
5 - White connecting to Yellow - OK (diagram does not say the color of this yellow wire)
4 - Green connecting to Blue+Black - OK
3 - Blue connecting to Blue - OK
2 - Brown connecting to 2 Brown wires - OK
1 - Red connecting to Brown/White

Does anyone know if this set up is correct?

Also, does anyone know if there a relay involved with the Door Locks and which one it is?

Many thanks everyone

Bill Ball

I agree that connector wiring doesn't match the wiring diagram, but mine is the same as yours. And, yes, red going to brown/white seems odd to me as well.

Sorry, I have no suggestions for you yet.

westija

Quick update:
Checked YE/BL and GR/RE wires on Driver's Door while pushed the Central Lock Button at the Console (thanks for the tip Dan) and got 12V (for just a fraction of a sec). Then did the same on the Passenger Side at the Connector behind the Glove Box and got the same.
So, either I have a bad motor which somehow os preventing the other one to work; or a bad wire somewhere inside the Passenger's Door. I will try the latter first once I reassemble my Driver's Door and some other things I have pending now.
If any ideas come up, please let me know.
Thanks

Dan87951

My Cassirot is apart for a paint job. I will run out there with a DMM and check the voltage I'm getting at the door motor but I'm pretty sure it should be longer than a second.

Dan87951

Mine holds 12V until the lock/unlock procedure is complete. Do you even hear the motor go for a quick second (since you get 12v for a sec)?

westija

Dan, thanks for checking that.
No, cannot hear anything, it is like no motor is running from any side (driver's or pasenger's side).
Really weird to have two motors down, but since I bought this recently, who knows for how long they have been like this.
Today I disassembled the motor from the driver's side and was hoping I could look into its guts, but as you probably know it is a sealed piece.

Does anyone know how to test the locking motor outside of the car? If I only could get it tested to eliminate it from the troubleshooting...

Thanks and best regards

MainePorsche

Would be very odd to have 2 motors go down.
Check wire integrity at harness stress point at the front of the door.

Dan87951

Seems odd both motors would be bad, I agree. If you have a 12v power supply or use a car battery you can test your motors that way.