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Discussion Starter #1
So, the classic issue with central locking is the biggest problem left with the new car. PO said that he had replaced the central locking module, but it did not fix the issue. It sounds like things are pointing toward the drivers door micro-switch.

So, onto the fun symptoms. Doesn't seem to work at all until it gets hot outside, and then:

-Only rear doors and gas cap will actuate from the central locking button.
-In same conditions, can get rear doors to actuate from passenger side door lock.
-Drivers door will actuate rear doors once in a while (i.e. when it is a full moon outside), and only once.
-Front doors will not activate at all through the central locking system.
- Drivers door will show open and closed correctly on display, and cannot lock the door when it is open (like normal).


What do these issues seem to point to? Is it the micro-switch or another issue?
 

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The symptoms you describe are so disparate and inconsistent, it would almost certainly indicate an intermittent problem within the CM.

I don't mean to cast aspersions on the PO, but is it possible that he replaced the control module with a used part?

The first time I tried to fix a wide spread central locking issue, I tried 3 different modules from the J/Y before I got a good one. Since then I just fix the one I have.

I would do one of the following:
1. Go to the junkyard and get another CM (maybe 2-3)
2. Order a new one
3. Fix the one you have

Repairing the one you have is usually the easiest/fastest solution.

Assuming you know where it is located - remove it from the harness and put it on the bench.

Open the cover and inspect the solder joints. Specifically at the interface of the harness pins to the PC board. These soldered joints are almost always the problem.

I have had nearly 100% success rate reflowing those soldered joints - admittedly not that many repairs - maybe 5 or 6.

I never really had to go up into the PC board.

I didn't have to because there were obvious cracks where the external connector pins interfaced with the board. Use a magnifying glass and they will jump right out at you.

Just use a clean 25W soldering iron (pencil tip).

Use just enough solder to tin the tip. No additional solder is required to reflow the joint - and adding more solder will often cause bridging (see below).

IIRC there are 6 connections. Do each, one by one. Only touch each the tip to the interface long enough to melt the solder.

Watch the surface, when the solder changes color from dull to shiny it's re-flowed. Remove the heat and move on to another joint - preferably one not close to the one you just did. Also listen carefully while applying the heat. When a previously soldered joint re-flows it will emit a tiny squeak sound. As above, stop and move to another joint.

The area will get HOT. Give the board time to cool off between re-flows. Some of the nearby components are heat sensitive and overheating will damage them. Also it will prevent you from burning your finger tips.


Be careful of bridging - causing a connection from one joint to the adjacent one. If this does occur, run the blade of a utility knife between the bridged joints to remove the excess solder.

Also, on the outside, check the connections between the pins and the harness plug. Maybe give each stab a little twist or bend to assure good contact in the female half of the connector.
 

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Discussion Starter #3 (Edited)
Thanks, I'll try to resolder the connections and see if that improves the situation. CM is in the driver foot well area if I remember, correct?

Don't know if the PO replaced it the CM with a used one, but seems quite possible.
 

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Yeah, the module is above the drivers side "fascia" as they call it (that upside down piece of carpeted trim under the dash). It's out towards the wall. To remove, I think, it just slides off a clip.

When you have it out, just pry the cover off with a little screwdriver. One side will be pretty empty - the other side will look like this:




The yellow lines indicate the joints that usually fail.
 

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Discussion Starter #5
okay, got around to pulling out the control module today. All of the connections looked good, but just to make sure it wasn't a problem, I reflowed the solder joints and cleaned up the pins. Didn't notice a difference when I popped it back into the car.

Back to the microswitch again?
 

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You know, I skimmed over that part about the system not working at all until the ambient temperature rises. Did you check your ground points - there are 3 for the CL system:

Grounding Points</B>
G6Grounding point, negative distribution terminal, in the main fuse box (22B) behind the glove box.G8Grounding point, dashboard, by the left-hand front loudspeaker socket.G14Grounding point, left-hand front seat member.


Wiring diagram:




Component key, description of operation and fault finding:


COMPONENT ID


22aMain fuse board behind the access panel in the glove box.175Control module, central locking system, on a bracket under the dashboard on the left-hand side.184DMotor, central locking system, in the driver's door.184PMotor, central locking system, in the passenger's door.184RLMotor, central locking system, in the rear left-hand door.184RRMotor, central locking system, in the rear right-hand door.208Door lock indication, in the locking mechanism inside each door.213Pictogram, in the main instrument display panel.230Distribution terminal (+30 circuit) in main fuse box behind the glove box.274Microswitch, beside the lock cylinder in the driver's door.289Control module, anti-theft alarm, on the right-hand side under the dashboard behind the knee shield.434Motor, central locking system, fuel filler flap, adjacent to the fuel filler flap.435Microswitch, beside the lock cylinder in the front passenger's door.514aSwitch, simultaneous actuation of the central locking system, in window lift switch assembly (386) on the centre console.583Control module, anti-theft alarm with immobilizer, under the dashboard on the right-hand side behind the knee shield.2-Pin Connectors</B> H2-14In the right-hand front door, beside the locking mechanism.H2-16Beside the locking mechanism inside the right-hand front door.H2-30In the right-hand rear door, beside the locking mechanism.H2-34Beside the locking mechanism inside the left-hand front door.H2-36In the left-hand rear door, beside the locking mechanism.H2-73Beside the locking mechanism in the driver's door.H2-74On the right-hand side in the luggage compartment beside the central locking motor for the fuel filler flap.4-Pin Connectors</B> H4-13In the left-hand front door, adjacent to the microswitch.H4-19In the passenger's door beside the locking mechanism.10-Pin Connectors</B> H10-14In the luggage compartment to the left beside the rear filament monitor.H10-22In the right-hand B pillar.H10-24In the left-hand B pillar.22-Pin Connectors</B> H22-1Behind the cable entry in the left-hand A pillar.H22-2Behind the cable entry in the right-hand A pillar.Grounding Points</B> G6Grounding point, negative distribution terminal, in the main fuse box (22B) behind the glove box.G8Grounding point, dashboard, by the left-hand front loudspeaker socket.G14Grounding point, left-hand front seat member.
DESCRIPTION OF OPERATION
With the key in the driver's door or front passenger's door, all the car's doors and fuel tank filler cap can be locked and unlocked centrally.

Control module 175 for the central locking system is continuously supplied with current via fuse 16.

The control module is controlled from microswitch 274 in the driver's door, microswitch 435 in the passenger's door or from a switch in switch unit 386 in the centre console.

When the doors are locked, terminal 2 of the control module is grounded and current is supplied for 0.7 seconds to all actuating motors, closing the locks. The motors are grounded via terminal 8.

When switch 514a (LOCK) on the centre console is activated, terminal 5 of the control module is grounded and current is supplied for 0.7 seconds to all actuating motors, closing the locks. The motors are grounded via terminal 8.

When the driver's or passenger's door is unlocked, terminal 1 of the control module is grounded and current is supplied for 0.7 seconds to all actuating motors, opening the locks. The motors are grounded via terminal 7.

When the switch on the centre console is activated (by pressing the part of the switch with no symbol), terminal 6 of the control module is grounded and current is supplied for 0.7 seconds to all actuating motors, opening the locks. The motors are grounded via terminal 7.

If the driver's door is not completely closed and an attempt is made to use the central locking system from this door or from the switch on the centre console, it will not be possible to lock the doors.

If an attempt is made to use the central locking system from the passenger's door when the driver's door is not completely closed, the control module will lock the doors, only to unlock them again shortly afterwards.

FAULT DIAGNOSIS HINTS

  1. Check that fuse 16 is intact and supplied with current.
  2. Check the connectors, wiring harness and ground connections.
  3. Check that terminal 4 of the control module is supplied with current.
  4. Check that current is supplied to pin 8 of the control module when the doors are being unlocked and to pin 7 when they are being locked.
IMPORTANT
Control module terminals 7 and 8 are live for only about 1 second , so readings on them must be taken at the precise moment when the locking mechanism changes position. In the inactivated position, both outputs are grounded.

Note also that the actuating motors (on testing) should be connected only to pins 7 and 8 of the control module. Otherwise the motors could be overloaded and damaged.

 

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intermittent and temperature dependent failure of the central locking system is very typical for a 9000 and caused by bad relays in the central locking unit. The internal relay contacts burn in, only visible if you remove them from the pcb and break them open. Often the door motors also operate at limited power as the poor condition of the contacts causes too much voltage drop.

As the relays housings are flimsy and plastic, the heat from resoldering the pcb will release some material stresses and deform the relays slightly causing the internal contacts to shift just a tiny bit. Which sometimes is enough to get some new life out of them for a (short) while.

But the better solution is to replace the 2 relays in the unit by soldering in new ones. Did so on a couple of 9000's and none of them had any problems since. As the original relays are obsolete and it is hard to find pin to pin compatible ones you might need some ingenuity to get them on the pcb but anyone with some experience in electronics can do it in 5 minutes.
 

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Discussion Starter #9
Looks like I have some testing to do next weekend on the electrics, been having some fun today with a stage 3 tune :cool:.

@90000006 Do you know what the relays specs are? Didn't look when I had it out. Do you have a specific relay that you used to replace them previously?

I'm thinking if it is narrowed down to the control module, I might just spend some time at the mechanics yard. Pull a handful of boxes and start swapping them in to see if one fixes everything.

@dmgb5, All over the place, but at the moment I spend most of my week in Hillsboro. The car used to belong to a tech at Atomic, actually, picked it up at the end of April. Beckner is my mechanic for the tougher work on the car, however.
 

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Don't remember exactly what I put in but I can tell you the specs: The relays are SPDT (single pole double throw), coil resistance > 150 ohms and coil voltage 9-12 volt. The contacts should be capable of 10-15 amps. There are a lot of standard relays out there that will meet those specs, just pick what's available. As the replacements I used did not have the same footprint I connected them with short wires and glued them to the pcb.

All door motors are wired in parallel so if you have problems on one specific door you have to check the motor and mechanism there as well. The door motors have standard size and mountings so finding replacements is easy.
 

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@chengny: Here's what a relay contact of a typical 9000 central locking unit looks like after 15 or so years of service. Not much chance of curing this by reflowing the joints :roll:

 

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Hope mine do not look like that _ I have 3-9000's and a C900!~!
 

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no worries- replacing the relays is just a 5 dollar fix ;)
Maybe I should take a look, preventative measures.

I have 2 MY 93, 9000s, and one My 97 9000, and a 92 C900 vert.

Plenty of opportunity for failure!
 
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