Central locking not working

[jc_uk]

Hi,

I have a problem on my Elan with the central locking.
Fitted from new with a Gemini alarm connected to the central looking.

With the doors open it works erratically and not consistently.
With both doors closed it will no longer lock.

Lots of motor/actuator noise from both doors, but not locking.......

Any ideas on how to debug this one please?

Also I can see a wire that had dropped down from behind the glove box
Any idea what this is for please?

Many thanks
JC

[peteoddcar]

Hi Could we have a little more info to try to help track it.

With the doors shut do the lock buttons stay down if manually pushed or lock with the key ? Is there any interaction between the doors in that state? Ie does the passenger follow the driver or visa versa ?
No idea about the cable can you see when it comes from if you drop the glove box
Is it Grey

[peteoddcar]

Closer picture of the nd of the cable looks as if it might be braided?

[jc_uk]

Hi again,

The cable is black outer, with clear inner and then twisted copper core.
Could this be some kind of aerial for the gemini remote locking?
The wire disappears into the thick look of wires behind the glovebox.

With the passenger door open, the locking of the doors with the remote seems to work as required, and the alarm is armed.

When I close the passenger door, it no longer locks........

Open the door and it works again......

Thanks
JC

[jc_uk]

Hi,

With both doors closed the locking works as expected with the key, with both doors locking and unlocking with the turn of the key.

With the passenger door open, locking the drivers door locks both doors, and then the open due to the passenger door being open.

With both doors closed, when using the remote it seems like the doors are trying to lock but not enough power to complete.......

Any ideas?
Or what to look at next?

Thanks

JC

[peteoddcar]

Well that is a bit odd. Pretty much all working as it should is the car an S2 with its original alarm ? Or S1 with the factory option ?
It seems that there’s a bad connection on the lock line from the alarm module, or the alarm module has a poor power feed or most likely a poor ground

[Saltire]

As I said in my PM, it would be worth checking out the manual’s description of the SE central locking arrangements, in particular the two separate door switches. You can find this through the “Manuals” link at the top of any forum page (Section MJ9, pages 23-25).

[Tuga2112]

I am pretty familiar with the SE's central locking system.
i have not only added a remote unit to mine to connect tot he integrated central locking in order to operate it, as well as tagged my window controller board to that in order to close the windows then the doors are locked.

your description of operation is very strange because it suggests that the power source for the remote locking is different from the power source from factory (if using the keys works fine and using the remote theres not enough power to operate the solenoids. )

i suspect your gemini alarm is trying to open and close the solenoids directly (connected to the Yellow/Blue or Yellow/Pink wires).
instead of the alternative instalation (which i believe being correct, but im sure someone else will disagree) where it intercepts the switch wire (yellow/red) and bypasses its state pretending to have opened/closed a door, which then operates the CDL module as if the key opened the lock.

the difference is that you need a high current being pumped into the yellow/pink wire to operate the solenoids. however if you "fake" an opened door by intercepting the Yellow/red wire, you need virtually no current, and then the CDL does the heavy lifting for you (using the thicker wires that came from factory) to activate the solenoids

if there is some serious kinks in the wires from the geminy alarm. those wires would not be able to pump enough current to activate the solenoids. which in turn give you the impression of an attempt, but not enough "power" to get the job done

now that you know all the theory here's the practical application of my suspisions.

go to the side where the alarm is fitted. look at the place where all the wired for the door come. and follow the yellow/pink and yellow blue pair, you should find that they have been spliced at some point.
folow the spliced cables. search for anything that may be kinked or cut or damaged. Unkink it, and try the remote again.

if the remote starts working, you need to replace that section of wire. if it still doesnt work, continue folowing the wires.
ultimately, it could be something internal to the alarm and the unit may not be able to put out enough current to operate the solenoids.

Alternatively as pete said. if the grounding of the gemini alarm is faulty, again, the alarm circuitry woudn't be able to supply enough power to the solenoids.

either way, this is just a guess from hundreds of miles away, so, i may be going on a complete tangent there.

[GeoffSmith]

I have a BNIB CDL module if you need it (I don't think I need it as I'm pretty sure the S2 doesn't have one). It's somewhere in the loft and I think it was about £25.

[peteoddcar]

You’ll not find me disagreeing with that great description - that’s exactly how my car was set up when I bought it with the alarm module diving the motors directly.
It’s the yellow red trigger wire that needs driving from the remote module/ alarm to make it work correctly.

[peteoddcar]

JC where are you located ? If you’re not far from Essex maybe I could assist you?

[peteoddcar]

I think the mystery wire is probably a defunct interior scanner cable

[Tuga2112]

You’ll not find me disagreeing with that great description

certainly whoever installed it like that will disagree. (unless the alarm does not have the option to be installed like that)

JC.
if your near Durham, I can have a look and sort that out (the rant about 90's "professional auto electricians" being complete idiots is included in the offer. )

when it comes to Electrical stuff theres usually many ways you cat may be skinned. only way to really know what went wrong is to trial untill you fix the root cause.
People default to the "check your grounds" advice because its the most common reason for faults in the M100
I like to propose the alternatives.

[peteoddcar]

I agree The aftermarket / dealer fit quality in the90s was in most cases poor at best.
It was a headache for us Lotus electrical engineers as so many of the warranty claims had the route causes in aftermarket installs - we got a lot of pressure from Managment to reduce the warranty costs which in a way was out of our control.That’s why there is do much detail in the manuals to install the Lotus approved system and the S2 got alarm as factory fit.
Still so many people have issues - contact a local alarm installer who throw another system onto the car rather than diagnose - make more cash that way
There are exceptions some company’s do a good job.

[jc_uk]

Hi again,

Sorry for long break, but back looking at this again......

The car is a first series SE Turbo H reg - I purchased it at 6months old and have run it since, from home nr Kendal, South Cumbria.

The alarm appears to factory fitted - Gemini according to the sticker on the car window.

Checked manual MJ09 p23-25 and all matches up to the car.

Again trying the remote today I get the same behaviour -
- with the passenger/driver doors closed, the remote doesn't activate the central locking
- with the passenger door open the remote activates the central locking on both doors and can lock and unlock the doors......

Also with the passenger door open, the internal/mirror lamps are activated, and when closed they time out and turn off, as expected.

Can anyone tell me how the system senses that the doors are open/closed please?
Also how do I go about fixing this issue?
(door card currently in place on the passenger door, but I can see it coming off before the weekend......)

Many thanks

JC

[Tuga2112]

this is a TLDR response.

but the system sensing the doors being opened or closed is based on a yellow wire with red stripe which carries a small +12v current.
from factory (and very likely your alarm instalation had changed this setup) this wire is attached to the CDL module.
if the door is open. that wire is an open circuit and will read 12v (or some figure very close to the battery terminal voltage).
when a door is closed, that wire is connected to the ground and its voltage reading should be 0 (or some very low number)
the CDL tracks the voltage of this wire, and triggers the locks on both sides depending to its intended behaviour given the current state of the doors

you can read all the details about how it functions in the electrical manual.

alarm instalations may directly lock and unlock a door (usually driver side) which then triggers this wire to make the CDL work OR the alternative instlaation (and some will argue the correct way) is that this wire is cut and connected tot he alarm unit so that the alarm unit simulates the 12v or ground state in order to "trick" the CDL to open/close the locks

due to the high current required to trigger solenoids. its usually a bad idea to install an alarm that triggers the solenoid directly. an electrician with intermediate skill will add a relay to the system in order to avoid the alarm from directly acting on the solenoid. but a lazy one may get away with the direct connection which is likely to shorten the life expectation od the alarm unit.


SE cars do NOT have a factory fitted alarm. its at best, been a dealer instalation. but most likely not (most owners that installed were not willing to pay dealer prices)

from your descrption. it sounds like the yellow wire previously mentioned has been cut (or internally damaged) between the passenger door and the CDL

this is just a guess based on my knowledge of installing my own remote locking system and afterwards using that yellow wire to trigger the windows controll unit i made to close the windows when the doors lock

[jc_uk]

Hi again,

Is the following the door ajar switch referred to in the manuals?
C100B6065F LIMIT SWITCH Lotus Elan (1989 onwards)

If so where do these sit in the door and how do i remove/replace etc?

Any docs/photos to help please?

Many thanks

JC

[M100-NC]

Switch C100B6065F is part of the door latch.

Section 10.17A, page 2 in the S2 parts book page 2.

Door Handles & Lock Mechanism

Page 38 in the downloadable parts guide S2

You can also read page 159 (BK.2) in the Lotus Service Manual available in the manuals available at the top of this page.