Author Topic: Power wire to preventative ignition switch left disconnected?  (Read 2550 times)

Green68MB

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Technician failed to reconnect the black power wire between a toggle underneath the dash and the starting pathway. This has left the kill switch inoperative.  Key works fine.  To provide me with peace of mind I had the cut off switch installed so that the ignition/key  would not operate without the toggle in sequence.
    I had a new Bosch 15 coil and new starter installed, serviced cold start and distributor converted to transistorized.  The wire seems to reach to the coil.  Can anyone advise me which component  to reconnect to, that would most effectively provide the stopgap. Thanks

lpeterssen

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #1 on: July 23, 2022, 11:33:13 »
Dear friend

An easy way to kill a car motor from working is to remove the fuel pump fuse. It  Is the fuse no.4.  The car will start with the remaining fuel pressure on lines but will stahl immediately after.

Best regards
L.pteressen
« Last Edit: July 23, 2022, 11:38:29 by lpeterssen »

Green68MB

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #2 on: July 25, 2022, 01:03:57 »
Thank you for your response, I have seen numerous informative comments you have noted within the forum and hope you can provide  me with direction.
     The toggle previously mentioned is under the dash, out of view and worked fine until my mechanic not remembering it existed, simply disconnected  it and never reattached it to the appropriate component.

If the black (non ground) wire is attached to the positive pole of the coil and the toggle is switched off will it interrupt the command to start the engine? 

Desertpagoda

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #3 on: August 06, 2022, 23:27:05 »
I dont think the switch u mention was installed by MB
kb

Green68MB

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #4 on: August 18, 2022, 00:03:07 »
Thank you for your reply.

           A Lamborghini  dealer in NJ installed the switch to prevent anyone tampering with the key ignition process. 
   It effectively prevented starting  using the key unless you flipped the toggle and the electrical circuit was engaged.

   As I said, the tech guy simply forgot to connect the existing loose wire. Now it starts  normally. and I must rely on the original  system.  This leaves me with 1 less security system when parked anywhere,

Cees Klumper

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #5 on: August 18, 2022, 00:45:57 »
It's counter intuitive that a non-connected wire to a kill switch allows you to start the car normally. It sounds more like the tech bypassed the kill switch, by connecting both wires to the same switch terminal, than that he left one of the wires disconnected. I would look behind the dash to see whether that is what he did, and, if so, move one wire to the other kill switch terminal to restore its function. If that fails, my advice is to take it back to the tech, or another shop, to figure it out.
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

Green68MB

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #6 on: September 25, 2022, 16:35:03 »
The car starts fine, The originally  lambo dealer installed switch( that DID prevent starting UNLESS engaged-under the dash) _ WAS NOT RECONNECTED.  i WANT TO reconnect THAT LOOSE UNDER THE DASH SINGLE WIRE SO THAT i HAVE A SAFE GUARD/STOP GAP BETWEEN THE IGNITION  SWITCH AND ITS STARTING PURPOSE SO  I HAVE MORE PEACE OF MIND WHEN LEAVING IT SIMPLY PARKED IN ANY DRIVING AROUND.   Any advice as to where to reattach it, solinoid,  cold start, etc will be informative.   Thank You

BobH

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #7 on: September 25, 2022, 17:32:08 »
Hello, what Cees is saying is that a toggle switch in the normal position would keep a circuit closed, if one of the wires was disconnected, it would be the same as the toggle being operated permanently and the car would never start

The fact that it wasn't originally installed when it left the factory means there is no circuit diagram to refer to, and it's almost impossible to advise where the wire may go without an electrical engineer tracing the circuit

If you look at the toggle switch and see 2 x wires connected together, you need to separate them and connect 1 x wire to the other terminal.  If there is only 1 x wire connected i wouldn't connect this loose wire until you know where it goes to in the engine bay, if you connect it incorrectly you could at best blow a fuse and at worst burn out the wiring loom.  it might be possible that the dealer installed a relay, that energises when the toggle was operated, but it would be unusual, and would flatten the battery quite quickly
« Last Edit: September 25, 2022, 18:35:41 by BobH »
February 1965 230SL Automatic
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Green68MB

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #8 on: October 06, 2022, 22:43:24 »
Thank you for your interest.  There are 2 wires connected to the toggle, one is grounded within the interior(to the metal/dash) the second runs through the firewall and is zip tied to a hose adjacent to the coil. The wired contact connector is sealed off with electrical tape.  It would seem that this wire was attached to one of the initially mentioned components.
   If the toggle was  engaged no circuit was open and no starting capability would occur.   Essentially it prevented the completion of the circuit.  It did work for over 20 years.
  Yes, I understand the fuse/fire issue so it is why i have not experimented... And as it is an accessory I have no interest in bringing up the lack of re-connection to my mechanic as it ism important I keep his talent available.
Thanks for your thoughts.

Cees Klumper

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #9 on: October 07, 2022, 08:03:11 »
The only thing that comes to my non-electrically-trained mind is that your mechanic moved one of the wires that used to go to the toggle switch directly to the ignition switch, restoring the original 'path' that provided power to the starter motor. So, originally, we have a plus wire from the fuses to the ignition switch, then from the ignition switch straight to the starter. Your lambo dealer may have 'inserted' the extra toggle switch into that outgoing (from the ignition switch) power wire to the starter, thus requiring the toggle switch to be in the 'on' position for the starter to be able to work. Your mechanic may have seen all this and decided to restore the original circuit, by routing a new wire directly from the ignition switch to the starter, bypassing the toggle switch. With no further function, he disconnected the now useless wire that ran from the toggle switch to the starter.
That, or the toggle switch was inserted in the power feed to the ignition coil or the distributor, in which case something similar:  your mechanic ran a new wire from wherever the toggle switch got its feed, directly to the ignition, bypassing the toggle switch that now no longer has a function, hence the disconnected wire.
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

BobH

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #10 on: October 07, 2022, 08:17:45 »
Thank you for your interest.  There are 2 wires connected to the toggle, one is grounded within the interior(to the metal/dash) the second runs through the firewall and is zip tied to a hose adjacent to the coil. The wired contact connector is sealed off with electrical tape.  It would seem that this wire was attached to one of the initially mentioned components.
   If the toggle was  engaged no circuit was open and no starting capability would occur.   Essentially it prevented the completion of the circuit.  It did work for over 20 years.
  Yes, I understand the fuse/fire issue so it is why i have not experimented... And as it is an accessory I have no interest in bringing up the lack of re-connection to my mechanic as it ism important I keep his talent available.
Thanks for your thoughts.

If one side of the toggle switch is grounded, this means that the loose wire in the engine bay, is part of the closed circuit that grounds one of the starting circuit components.  I don't have my car here to see what other components are close to the coil.  is the starter solenoid/relay located close by?, one side of the relay coil is grounded, so the toggle circuit could interrupt this ground, and the mechanic could have restored the ground connection, thus bypassing the toggle switch.  I guess there are other parts of the ignition circuit where open circuiting the ground connection would inhibit starting.  I guess you need to find whatever is close to the end of this loose wire that has a ground/earth wire
February 1965 230SL Automatic
UK delivered RHD
Papyrus white, blue hard top & hub caps
Blue soft top
Blue leather

lpeterssen

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Re: Power wire to preventative ignition switch left disconnected?
« Reply #11 on: October 07, 2022, 11:04:51 »
Dear Friends

It is important to consider that mechanic who disabled the toggle switch did it for a reason.  If it were a perfectly functioning system he wouldn’t  have to mess with it.

In my honest opinion to have a simple toggle switch hidden to cut signal going to starter selenoid is not a good idea. I mean only a switch.  I say that,  because if it is a hidden switch, it should have a small form factor, therefore it will be designed to pass through a small current value, not the kind of amperage that a T50 signaling cable has.  In order to do it right the toggle switch should be only used as a signaling device like for example giving a ground signal to a relay, that will switch through its high current terminals 30 & 87 the energy going to the starter selenoid T50 line.

If the toggle switch on the other hand, is used to cut energy going to the coil resistance, also the same kind of thinking applies.

In any case I think that the best approach is not to mess with those cables that mechanic disconnected.  Maybe the switch was kind of defective and not passing enough current to the interrupted circuit, and that may have been the core reason why the mechanic that worked on the car had to remove those leads from passing through it.

The best solution, and is not to make propaganda of myself, is to send me the whole harness during this fall/winter season to service the harness, repair all hidden damages that may be there and to install properly a toggle switch
/ relay or an embedded alarm system.

I am sure that what the Lambo dealer charged for installing that toggle switch will be about 1/2 of what I will charge our friend Green 68 to service all that harness in full. So let me do the work right, and do not cause major harm to that car electrical system.

Please contact me to do it right

Best regards
Eng. L.Peterssen

« Last Edit: October 09, 2022, 20:41:26 by lpeterssen »