Immobiliser bypass central locking function

[RichardH]

My S2 has had a immobiliser issue three times now, where it will not disarm if the battery is anything off max power. This last time it has done this is while at the Lotus specialist (where it remains) while having other work done. Their evaluation is that after 31yrs the immobiliser has died, and I have decided that rather than have future issues, to get them to bypass it, and I will use the battery isolator instead. My insurance is up at present and interestingly they are not bothered if it has one or not.
I believe though that the central locking will be lost by this action as it is activated through the immobiliser, and would like to install a simple kit to replace this functionality. I have looked through the manuals I have, but cannot find any wiring diagrams to follow for this to be undertaken, and wonder if anyone has done this could they share the information.

[chrism]

RichardH, I can't offer to contribute but I'd be interested in your 'fix' too.

I have a receipt from 4 years ago for a firm to remove the Gemini Aquila alarm that was retro-fitted (weren't they all?) to my '90 SE, and install a 'kill switch'. (I understand they could be a bit of a 'mare for various reasons...)

I've found the kill switch but it doesn't appear to kill anything. I've 'multimetered' the switch itself - which seems to be working okay but it seems to have no effect on fuel pump or electrics. The car starts + runs normally whether that kill switch circuit is on or off

I phoned the firm and they remember the job. They said they think that they'd normally use the existing Gemini wiring but couldn't (or wouldn't) explain/remember/advise where I needed to investigate next - and taking apart the dash to trace wires fills me with absolute dread .

Any advice that you glean - or more widely from my LEC pals - would be mucho-appreciated...(I obviously understand if it would have to be PM'd)

ps I have central locking by key and button from the driver door which activates the pass door button. However the pass button doesn't activate the the driver side; I've got a feeling that this may be 'standard' to my SE tho'.

I may be wrong, but I suspect yours might be an alarm /immobiliser only that makes use of the existing cent lock function - but I'd be happy to be corrected by someone who knows more and who might assure me that my cent locking is an original feature of the car...

[Tuga2112]

being a S2
Jonathan probably will come along with he's guide. which is not in public domain for obvious reasons.

you can ask him about it next year at CC Chris

[chrism]

you can ask him about it next year at CC Chris
Yeah, not proud to have 'wimped out' of CC'25 due to the weather...

[RichardH]

Look forward to hopefully hearing from Jonathan. I quite understand the reason for the info not being on open forum, but with the existing setup terminal, it would be nice to get the car back up running, as close as possible, to how it used to be.

[Saltire]

You rang, João?

Apologies for not replying sooner, but I have been marshalling all weekend for our village 24 hour charity bike ride (and yes, some mad individuals do ride the entire 7 mile course throughout the whole 24 hours with the occasional break. The rest are in teams.)

OK, back on topic:

- On the SE, there is a separate central locking module under the dash on the driver’s side (RHD). SEs were not factory equipped with an alarm, but there was a service note for Lotus dealers, who fitted the Lotus recommended unit if the customer requested it. The S2 has no separate central locking module; that function is integrated into the factory fit Gemini Aquila alarm/immobiliser.

- when I replaced my S2 OEM Gemini Aquila with a new alarm/immobiliser (which had an integrated locking facility), it was relatively easy to tap into the appropriate wiring. I could have gone in at the door harness connector, but as I was replacing the Aquila anyway, I just picked up on the existing wiring. The bottom left hand corner of Sheet 29 in the S2 Wiring manual (accessible through the Manuals tab at the top of a forum page if you’re logged in) shows the central locking wiring connections and colours.

- I have a fairly comprehensive write up on the installation of the Aquila in the S2. Pinky also holds a backup copy (just in case I win the lottery). As João says, I don’t post the details on the open forum, but I’m quite happy to send the pack by email if you contact me through the email address in my profile. Be warned: it’s picture-heavy and about 8Mb in size.

[chrism]

Hi Saltire. Yes please I for one would like to know details of how the Aquila works. It was retro-fitted to my '90 SE, then taken out by a subsequent owner 4 years ago. (Sirens have been left in place behind the coolant res and wheel arch tho' )

Apparently the 'kill-switch-that-doesn't-kill' was wired into the existing Aquila-type fitment at the time of removal so I need to know the lie of the land. I strongly suspect it's an electrical inhibitor cos the wires from the toothless kill switch seem to go towards the right where there are fuse-boxy and relay types of stuff...

If you don't want to stretch the security aspect then please, at least, pm/tell me where I ought to be looking - and what I might expect to recognise - since I don't have an Aquila circuit diag. It might only be a relay or perhaps even a fuse renewal that gets me back to having a useful immobiliser

[Saltire]

Chris

You’re more than welcome to a copy of what I have, although it comes with the caveat that it applies to the fitment of the Gemini Aquila as standard to the S2. An Aquila on an SE will have been fitted by a third party installer, and who knows how they will have decided to wire it. Specifically, the power feeds on SE and S2 (and therefore fuses) are different.

Unfortunately, I can’t tell you specifically where you ought to be looking on an SE, because that would require me to see inside the mind of whoever wired your alarm up in the first place. There are lots of different approaches. The S2s, because they were a standard fitment, are easier to deal with.

In the same way, I can’t simply PM you with the information I have, as there’s no way for me to send an 8Mb file attachment through PM on this forum. That’s why I ask for an email from you, so I can then reply quickly and effectively.

I’m sorry if this comes across as unreasonable, but I have a large - and increasing - number of requests for this information, and this is the best way I’ve found of minimising the time I spend on it and keeping track of who it’s gone to. Please do email me and I’ll be happy to reply

[chrism]

Hi Saltire. That's absolutely not unreasonable...

Thanks, I'm quickly realising that I've been getting that impression from the alarm removal firm; ie that 'whatever their solution was, we've added or modified and and used what they've given us...'

I was thinking/hoping that there might be an overall general immobilisation process that the Gemini Aquila (that was previously fitted) addressed - either starter or fuel circuit (or both?) - that I might be able to focus on to see if there could be a (simple) fuse or relay fault, since the kill switch appears to be wired into 'something' under the dash.

Yep I'd be really interested in your info to see if there's any clues that could be pertinent towards my own resolution and I'll gratefully send you my email details.

[RichardH]

Hi Saltire, firstly thank you for coming to my rescue in trying to get back to some reliability with the little car. If you could forward the information concerning the alarm/immobiliser that would be a big step forward, and hopefully put this gremlin to bed. I will contact you by email so you can send the file through.

[Tuga2112]

i dont know what safety procedures Jonathan takes.
if i was in Jonathan's position. that information would only go to people who provided a matching set of information with V5 driving licence and some home bill all in the same name and address.

which funny enough would exclude myself from being allowed the information because my driving licence name doesnt literally match any bill at that address