Central locking mystery

Hi chaps,

Another mystery, this time from my central locking. Had the drivers side (the off-side - right hand drive) apart a few times now and motor etc doesn't look bad. Today I took both front door cards off and decided to do some voltage testing. First thing to note is that both door outstations have a large L on them. Presumably the one on the drivers side should have an R on it? Both have AMR3357 on them too. Are the outstations interchangeable? Only difference I could see is that the near-side (LHS) one had 05-F-95 written on it and the drivers side (RHS) had 06-F-95 written on it.

The symptoms: neither of the front doors respond to central locking. The bottons on the remote open and close both back doors and disarm the alarm but that's it. The key locks the drivers door, back doors, the boot and the filler cap and arms the alarm. The key unlocks the drivers door, boot and filler cap but not the back doors. The key usually disarms the alarm but not always.

So, down to the voltage testing. Do the following values look right? All tests done with both front doors open.

Note: blue/red = key switch; green/red = central locking; purple/white = door ajar; pink/black = something to do with motors? orange/black = lock motor; orange/pink = superlocking of motor.

LHS (near-side) outstation tested between module and lock.

Blue/red: +5V all the time.
Green/red: 0V all the time.
Purple/white: 0V all the time.
Orange/black: 12V pulse on pressing the lock button or locking using the key but otherwise 0V.
Orange/pink: 0V all the time.

RHS (drivers-side) outstation tested between module and lock.

Blue/red: 5V all the time. Briefly goes to zero when key turned but otherwise stays at 5V.
green/Red: 0V when key turned clockwise. 5V when key turned anti-clockwise. No change on buttons.
Purple/white: 0V. No change on turning key in ignition.
Pink/black 0V. 12V pulse when button pressed to open. Nothing on lock button.
Orange/black: 12V on lock button otherwise 0V.
Orange/pink: 0V all the time.

Swapping the 2 outstations over didn't seem to have any effect, although strangely I thought the drivers door green/red wire was originally 5V clockwise and 0V anticlockwise but on switching back it was the same as the other one (i.e. 0V clockwise and 5V anticlockwise) so maybe I was mistaken.

Do these voltages stack up? Are the outstations interchangeable? If so then I guess the next step will be the microswitches although in this instance I'm not convinced there's an issue.

I will note that when I originally had the drivers door off the wiring loom hadn't been clipped in place properly and the electric window was sometimes clipping the wires. This may have damaged them internally.

Any thoughts welcome.

Cheers,

J.

If with the key in door lock and turned the car locks/unlocks - the Microswitch is OK....

If you have changed the outstations round and the problem still persists My guess would be a wiring fault - possibly from the BeCM to the outstation....

There is only two types of Outstation (as attached) - one for the Nav/Audio system and one for the other systems....both doors use identical outstations....

I would look at the wiring, where it might have been damaged and where it flexes between the A post and the door. Breakage is not uncommon.

OK. Worth a look.

I've just taken the lock assemply apart and had a good look inside. The 3 microswitches seem OK (Cherry DB9 written on the sides) but when I placed a 9V battery across the metal (switches removed) none of the motors moved. Moreover, there doesn't seem to be any kind of linkage between the motor and the cogs so I cannot see how it is supposed to drive it! Does anyone have any pictures of what it is supposed to look like?

Doubt 9V will do anything - not only from a voltage point of view but also from a current PoV too....

No cog on the motor shaft?

Latch Components....only thing I could find....as attached..

Datatek said:

No cog on the motor shaft?

Click to expand...

Need my PC to get some photos off the phone. The motor has what looks like a pickup coil on the shaft. Below this is a brown plastic cog but it doesn't seem to be attached to the shaft as such. So, although it meshes with the large black cog that moves the latch mechanism it has no visible means of being turned by the motor.

The second motor (presumably the superlock) is tiny and just seems to turn through 90 degrees and effectively disengages the motor cogs from the latch mechanism.

Saint.V8 said:

Doubt 9V will do anything - not only from a voltage point of view but also from a current PoV too....

Click to expand...

I had the motor away from the latch mechanism. 9V battery isn't bad. Would have expected at least a judder or similar. The microswitches are rated 4 amp so it cannot take too much oomph to shift it. I also connected it to a 12V power supply in my shed but again no movement.

I'll try wiggling the wires between the a-post and the door tomorrow. Hope that brings some joy!

Cheers,

J

OK, here's my first attempt at clipping on some pictures. Sorry for the quality of the photos. The phone isn't new and wasn't a top model when it was.

You should be able to see the brown cog but heaven knows how it gets its drive as the metal ring is bigger than the pickup coil type thing above it.

your c/l motors have burnt out, i would say that you have parked too close to a wifi hotspot. the brown cog gets turned by a very small cylinder that pops out from the white plastic fitting on the shaft of the motor due to centrifugal force. new mechanisms i'm afraid. i'm doing some research at the minute and rover 25 latches of a certain year may be the same, aswell as mgf/tf ones.

This problem occurs due to a faulty or old type rf receiver it sends a signal to the front doors to unlock lock and burns the motors out so before you replace the locks change the rf receiver or you will be doing it all again it is a common problem afraid. From memory there have been 3 different revisions to the rf receiver and they are about 150 quid or so from island 4x4 do not buy off ebay as you will be buying an old one with same problem

Ah. That kind of ties in with today's play. Hooked it up to a nanocom and I can send a lock signal to the door and hear a relay or switch click but nothing from the lock.

Heard about the infamous RF issue but cannot say I've noticed any symptoms. I'll try a battery drain test and see if the BECM goes to sleep. Assuming it does I assume I haven't got an issue ... actually. All that means is that I don't have an issue at home. Doh!

On another thought, any idea what amps / volatage the actual motors are? Is there an equivalent available from Farnell or similar? Sure it'd be reasonably easy to swap the motors and they probably only cost a fiver.

J

Grrrrrr said:

On another thought, any idea what amps / volatage the actual motors are? Is there an equivalent available from Farnell or similar? Sure it'd be reasonably easy to swap the motors and they probably only cost a fiver.

J

Click to expand...

Lots of folks have looked for replacement motors, not heard of any being found. Try Model shops.

Looking at the Schematic....

The BeCM feeds power to the Outstation from Fuses 9&22...The BeCM receives a signal either from the RF Receiver or the Door Lock Microswitch (via the Door Outstation) to activate the lock motor(s)....so the BeCM tells the Outstation to cycle the Lock Motors...which I assume is done with the power from either Fuse 9 or 22....I can only assume they are 12V motors....

Seeing as though you seem handy with a multimeter and a set of spanners - probe the multiplug and cycle the door locks - you'll need a pretty good meter as the power may only be on for a second and most cheap makes don't refresh quick enough to see the voltage spike....

As for current - without a working motor to probe on as it cycles, difficult to tell....

Somewhere in the dark deep recesses of my mind ,I recall some one saying they were Mabuchi motors.I dont think they were able to locate a supplier though.

JohnP38 said:

Somewhere in the dark deep recesses of my mind ,I recall some one saying they were Mabuchi motors.I dont think they were able to locate a supplier though.

Click to expand...

Mabuchi motors are fitted to many electric model cars. But may vary in speed and torque from the ones used by Land rover.

Interesting, interesting.

It is a 12V spike to cycle the lock. I think the microswitches had a 4A rating so that's probably a good place to start - or maybe start with 3A motor!

J

A quick Google (Mabuchi 12v dc motor) kicked up the following on Fleabay:

Mabuchi FK-280 Motor - 10 to 15 VDC - Trunk Lock Actuator DC Motor - 12V DC on eBay!

I think all is not lost!