Door locks

[Frustrated]

Help please!!! I am at the end of my rope. I have a 1990 525 with door lock issuses. The locks cycle when I either lock or unlock the doors, sometimes unlocking the car when I'm not around. The passenger side door lock tumbler cannot be actuated with the key and the trunk does not unlock with the central locking, only with the key. I have checked the wiring on the trunk arm and it visably looks fine. I have searched your arcives and have found mention of switches on the locks but am unable to locate them. I first noticed a problem with the trunk not unlocking the rest of the locks but it quickly progressed to the entire system. Where do I locate the switch? How can I test it? I have tried to syncronize the locks with your website instructions but it did not work, nor would the passenger door open with the emergency instructions. Any help is greatly appreciated as I have already started thinking of burning the car to the ground

[ukm5]

i think u have a mixture of issues here.

regards boot lock not unlocking with the central locking, id guess the motor has packed in on that lock, that would explain how it opens ok with the key

if your key doesnt turn the passenger door lock then id say the key mechanisum is damaged, presuming that key used to open it of course

when you say you have tried locating the switches, does that mean you have taken the door covers off and looked at the condition of them?

sorry you are having issues but on cars like these with electrical faults you just have to be calm and methodical, and really have a degree of electrical knowledge or they can have you over a barrel

[Kalevera]

EDIT: I'm an idiot and didn't read the post all the way through...disregard some of the following...


Do a search on the trunk wiring harness issue, mate.

The actuators are networked; when one of the six (four doors, trunk, fuel door) don't report being locked when the key is turned to LOCK, they're supposed to automatically unlock.

Wires in the loom for the trunk lid fray out; the trunk lock actuator is mounted in the lid; we talk about it all the time.


Each actuator has a microswitch inside of it that relays its status.

http://img.photobucket.com/albums/v736/suzpectx/lockacutator2.jpg

It's supposed to be visible on the PCB in the actuator above; however, that particular one had vaporized them, IIRC.

There's also a microswitch associated with the lock cylinder that dictates key position.

best, whit

[Frustrated]

I have a hunch it is the trunk switch, as that is where the problem seemed to have started, but am having trouble locating it. The gas door actuator is easy to locate but only has 2 wires to it. Does it not need 2 wires for power and 2 wires for signal? Can I test the contacts with an ohmeter? What color are the wires? Thank you for the reply

[Frustrated]

I think I will start with the trunk, as I do not want to disturb the door panels yet, and I am having trouble locating that switch. Where is it hidden? How come there are only 2 wires to the gas door actuator?

[ukm5]

well u will have trouble locating the switch if you dont remove the door panels

[ukm5]

reading what you have written so far, i dont want to get slated for giving a jerk reply, but i dont think u understand the circuits enough or will do to understand them and you wont solve this yourself

id advise you take it to an independant

[Kalevera]

Surely. But you might be stuck with that nick forever, frustrated :)

Trunk actuaor is accessible by unfastening the gray insulation (two plastic phillips speed screws, if I recall). The edge can be pushed out of the way around the latch mechanism. The actuator is sandwiched between the inner and outer stamped steel sheets, to the left of the latch. It may be a bit awkward to get an 8mm socket on it; it's been a while since I did one. The only uh....challenging....part of the operation is getting the assembly back together -- there's little room to manipulate the connecting rod...you'll see what I mean.

The actuators themselves really aren't serviceable. The unit pictured was cut open, explicitly for educational purposes.

best, whit

[Kalevera]

Oh, also -- I could be wrong about the gas door actuator being on the network. Javier will know. I know all of the doors and trunk lid work that way. Like I said, it's been a while since I've had to deal with an E32/E34 locking problem and I'm too lazy to go sifting through the ETM for a definitive answer.

best, whit

[632 Regal]

2 wires, one being the feed and one being the followup for the circuit.

there are microswitches on each door and the trunk lock which all on occasion fry.

I believe you can jump one micro at a time to isolate the problem.

I do not think the fuel door will cause a problem but is also part of the lock circuit.

[Gayle]

I appreciate this thread. I am having lock issues too. This is helping me a lot to understand the issues. Not that I plan to work on it myself, but I like to understand what is going on so I can decide whether I think the mechanic is feeding me BS. Thanks.

[Paul in NZ]

Frustrated..... the only way to check the condition of the trunk hinge wiring is to strio away the loom tape..I bet there are bare wires there.....
Locking problems seem to be rife at the moment.....

[Frustrated]

Frustrated..... the only way to check the condition of the trunk hinge wiring is to strio away the loom tape..I bet there are bare wires there.....
Locking problems seem to be rife at the moment.....
Thanks, I stripped away the tape and sure enough there was a short. Fixing it made the trunk lock motor to work but I still have the problem with the locks cycling. I metered out the circuit at the trunk and discovered that they reverse polarity to the motor to lock/unlock the door. There is also a set of contacts interlocked with the acuator to send a signal telling if the door is locked/unlocked. Do all of the doors have these contacts? Where is the control moduel located?

[Kalevera]

Thanks, I stripped away the tape and sure enough there was a short. Fixing it made the trunk lock motor to work but I still have the problem with the locks cycling. I metered out the circuit at the trunk and discovered that they reverse polarity to the motor to lock/unlock the door. There is also a set of contacts interlocked with the acuator to send a signal telling if the door is locked/unlocked. Do all of the doors have these contacts? Where is the control moduel located?
Frustrated...

It's a GM and Relay Module controlled system. If the RM were faulty, there would likely be other issues with the central body electrics.

I have a PDF of the schematic for the system from the ETM. Send me a PM with your email and I'll forward it to you -- the file's 108kb and I don't have any way of attaching it or linking it to the forum.

best, whit

[Frustrated]

I don't know what a pdf or etm is and I'm not sure what a pm is but my email is tl.baker@telus.net. Any help is greatly appreciated.