Bloody bodging!! Can anyone help..? :-D

[lordivanhoe]

Hey All, would welcome assistance with this one..

Was under the dash this weekend changing my indicator relay for the LED-friendly version, when I noticed the following rather 'interesting' thing; Picture attached!

To the left of my lambda unit is what I am certain is an inertia switch (black box, small red button on top).  Handy little device, useful for safety in a crash..  
Much less usefully, some bugger has clearly decided that safety be damned, they're going to bypass the bloody thing!  No wires going into it whatsoever.

So that's interesting...!

Well, clearly I'll be very keen to plumb that back in (or replacing it and then doing so if it turns out it's busted and that's why it was bypassed [tho that still doesn't excuse such chicanery!]), so the question then is: where the hell are the wires that are supposed to plug into it?

Now, also in this photo, interestingly, one can see a 'jumper wire' which has been plugged into a small light grey connector which sits a few inches above the inertia switch.  The jumper wire appears to be directly connecting a purple (maybe purple/black?) wire, from the middle of the block, to a black wire.  There's also a third wire in the grey connector block, which appears to be maybe brown/white (?) which doesn't currently appear to connect to anything.  Although I note that the intertia switch appears to have three spade connectors in the bottom of it.  

In 'Private Eye' lingo.. Could these facts be in any way related?

I would of course be very grateful if any kind and well-informed soul can shed any useful light and/or give any useful tips on this mystery!!  

Hope everyone had a good Bank Holiday.  In spite of the dangers, I took Bess to a local village car show, where she was very well received!

Cheers all.

[acmetowers]

The three wires are, black = ground,  brown pink = door unlock, black purple = fuel pump ground, so I guess black and black purple are shorted?

The idea is in normal operation the ground goes to the pump and when activated the car gets unlocked by the ground going to the central locking module (hence people trying to unlock their cars by hitting the inner wheel arch).

[Rissy]

As above. You’ll probably want to check out those wires. Black/purple wants to go back to the fuel pump connector on the fuel tank. Brown/Pink wants to make its way back to the door lock module in the relay compartment. Black is your ground. The inertia switch with the button pushed in, should short the black/purple to the ground for normal operation. On the event of you driving like a complete lunatic and putting the car on its roof or something daft, the huge ball bearing moves inside, triggering the button out and cuts the line to the pump, and grounds out the door unlock line on the door lock module instead.

[lordivanhoe]

Ah, thanks Rissy / Acme!
Makes sense.
I did of course suspect that one of the lines was the fuel pump, and assumed black was ground, but had no clue as to the third wire!  The knowledge that the inertia switch also grounds the door unlock, hence the third wire, is something I'd probably never have twigged!  :-D  Makes total sense now you say it, of course...
I'll do some (careful!) investigations accordingly and see if I can get the switch back in system!
Thanks so much!

[lordivanhoe]

So, now I know why they did it...
Removed the inertia switch and did a couple of quick tests (multimeter, testing resistance between the 3 spades with button down and also after a 'bump' with button up).
Result: No connection between connector spades with button in normal/down position!  So that'll be no power to the pump then.
When hit, and with button up, there is a connection to the 'other' spade.
So in the off-chance a stationary car could have an accident, at least the doors would've unlocked!!  :-D
Reading around, it's not unknown for these units to fail. 
Rather a shame a previous owner (or mechanic acting on behalf of!) didn't fix it properly, but I'll rectify that now.
Slowly ticking through that list of items..!

[Rissy]

When I bought my car nearly 13yrs ago, there was no inertia switch at all, and the part of the loom which has the connector for it, was also cut off short. The circuitry had been chocolate blocked in a fashion to basically allow the pump to run. Basically it sounds similar to your findings with your car. I had to buy a new inertia switch, and also lucky for me, also buy a second hand connector to put mine back into circuit properly again.

[lordivanhoe]

New inertia switch installed! Hurrah for safety. :-D

Also on my way to becoming a 'real' DeLorean owner, as my angle drive broke and I'm replacing that as well. ;-)

Ticking off those boxes!! :-D

[Rissy]

(17 May 2022, 14:00)lordivanhoe Wrote: New inertia switch installed! Hurrah for safety. :-D

Also on my way to becoming a 'real' DeLorean owner, as my angle drive broke and I'm replacing that as well. ;-)

Ticking off those boxes!! :-D

My new angle drive literally fell apart as I was fitting it to the car. They are very fragile. Like a delicate flower. Worked in my favour though, because as it turned out, it wasn't put together very well, or greased anywhere near adequately. I fixed both aspects and put it on the car successfully the second time around, and its been good for years and years and thousands and thousands of miles ever since. I recommend anyone to disassemble them before fitting them to weed out any imperfections and grease them up properly too.