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S4 micro switches & grounds

PostPosted: Sat Sep 15, 2001 9:32 pm
by "Carl Noble"
After digging thru all of the wires I finally realized that one of the
microswitches attached to the pull switch that breaks the vacuum to let the
head lights up, simply connects the headlight relay coils to ground (via a
black/red wire. It's actually that way on the circuit diagram.

Why go to all that work. Why not ground one end of the coil & leave it &
switch the "hot" (blue) lead. It would be a little work to change, but
seems much simpler -- especially since my micro switch is flaky. I'm
thinking abt putting in a standard pull switch with the usual domestic
contacts to do the switching. Not exactly in the spirit of proper
restoration, but more reliable.

Am I missing something? I've always kept grounds sacrosanct & never
switched anything in the ground circuit.

Thanks for any help. The list has been most helpful.

cheers, (no capital letters, but at least I can finally bring myself to say
it.)

Carl

S4 micro switches & grounds

PostPosted: Sat Sep 15, 2001 10:12 pm
by jopalm

Carl-

You could certainly do this (remove the microswitch that makes/breaks the ground to
the relay) and it would function just fine electrically.

I chose to restore my S4 to include the microswitches. Yes, it's plural on my car
because mine predates the "fail-safe" vacuum mechanism, so my switches are on the
headlight pods. One on the right-hand pod functions as yours on the vacuum switch,
the other on the LH side supports the headlight flasher relay.

One reason I chose to restore mine was to insure the headlights would not light up
while still retracted. If I turn them on before raising them, only my side lights,
parking lights and tail lights illuminate. The headlights come on only if/when I
raise them.

Conversely, if I raise them without first turning them on, the second microswitch
completes the ground to the flasher relay and the headlights flash like crazy. Not
terribly useful, but it's original and enough of an anachronism that I wanted to
preserve it.

Finally, don't condemn all switches in the ground circuit. They're actually quite
acceptable and used widely. Just two quick examples: That's what allows your wipers
to "self-park" and also how both your door microswitches and you dash switch are both
able to operate your interior lights.

In essence, multiple switches to ground allow any single one of them to make and
complete the circuit. (Yes, there's a second ground switch directly in the wiper
mechanism that's open when parked and closed during a "sweep")

In short, do as you see fit's your car and your situation. However, once understood,
these ground switches are actually quite useful!

Regards,
-John
'69 Lotus Elan S4 DHC #45/8290
'74 1/2 Jensen Healey #18918

S4 micro switches & grounds

PostPosted: Sat Sep 15, 2001 11:08 pm
by Rob_LaMoreaux




If you change it to switch the hot, you'll have to change the dip
switch to switch the ground. It's a moot point since one side is
switched to ground (to turn it on) and the other is switched to hot
(to selct high or low beam). Switching to ground is fairly common on
something where you want a failure to turn it on, or have multiple
points turn it on with a master off.

I'd just fix the microswitch on the headlight switch. If it is flaky
chance are that it is out of adjustment or the spade connectors are
not clean and tight. If it is the switch you can buy a new one from
many electronic supply places like Digikey (www.digikey.com).

Rob

S4 micro switches & grounds

PostPosted: Sun Sep 16, 2001 1:09 am
by TimMullen
John Palmer wrote:

My S4 Sprint with fail-safe headlights also two microswitches - but they're on
the "vacuum switch". One triggers the headlight circuit, the other works the
parking/taillight circuit. My headlight switch failed nearly 25 years ago - in
the middle of a tight hairpin turn, down in a canyon, on a dark night... =8-O

I swapped the two microswitches so I have headlights when the knob is pulled,
and use the rocker switch for the taillights...

Tim Mullen

Chantilly, VA
72 Elan Sprint

S4 micro switches & grounds

PostPosted: Sun Sep 16, 2001 2:27 am
by "Carl Noble"
Rob,

I understand the multiple-offs switching in the ground circuit(s) with a
master off (in series with the "parallel" ground switches) But couldn't that
just as easily be done by having the series/parallel in the hot side with a
single device ground. I could see the problem of having multiple hot wires
hanging around that could cause a problem if the wires became frayed, etc.
(I did some several thousand volt stuff many years ago -- but I always had a
competent EE around.)

I don't understand the "failure", proposition. I've never thought abt it
before, but let me try an example:. Suppose I have a lamp that is normally
on and it blows out. I'd like to turn on a warning lite. How do I do that?
I can have a relay that is normally closed (in series with the original
lite) that will open & complete another circuit. But that could be done
with the relay coils on either side of the lite.

I'm missing something. Please enlighten.

Cheers,

Carl
----- Original Message -----


Sent: Saturday, September 15, 2001 6:07 PM
Subject: [LotusElan.net] Re: S4 micro switches & grounds






If you change it to switch the hot, you'll have to change the dip
switch to switch the ground. It's a moot point since one side is
switched to ground (to turn it on) and the other is switched to hot
(to selct high or low beam). Switching to ground is fairly common on
something where you want a failure to turn it on, or have multiple
points turn it on with a master off.

I'd just fix the microswitch on the headlight switch. If it is flaky
chance are that it is out of adjustment or the spade connectors are
not clean and tight. If it is the switch you can buy a new one from
many electronic supply places like Digikey (www.digikey.com).

Rob









reserved.





S4 micro switches & grounds

PostPosted: Mon Sep 17, 2001 2:48 pm
by Elan45
Actually, there's another grounding switch right under your nose in the center of the wheel. Push it and you should hear a pair of clear hooters.

Roger


Carl-

You could certainly do this (remove the microswitch that makes/breaks the ground to
the relay) and it would function just fine electrically.

I chose to restore my S4 to include the microswitches. Yes, it's plural onmy car
because mine predates the "fail-safe" vacuum mechanism, so my switches are on the
headlight pods. One on the right-hand pod functions as yours on the vacuumswitch,
the other on the LH side supports the headlight flasher relay.

One reason I chose to restore mine was to insure the headlights would not light up
while still retracted. If I turn them on before raising them, only my sidelights,
parking lights and tail lights illuminate. The headlights come on only if/when I
raise them.

Conversely, if I raise them without first turning them on, the second microswitch
completes the ground to the flasher relay and the headlights flash like crazy. Not
terribly useful, but it's original and enough of an anachronism that I wanted to
preserve it.

Finally, don't condemn all switches in the ground circuit. They're actually quite
acceptable and used widely. Just two quick examples: That's what allows your wipers
to "self-park" and also how both your door microswitches and you dash switch are both
able to operate your interior lights.

In essence, multiple switches to ground allow any single one of them to make and
complete the circuit. (Yes, there's a second ground switch directly in thewiper
mechanism that's open when parked and closed during a "sweep")

In short, do as you see fit's your car and your situation. However, once understood,
these ground switches are actually quite useful!

Regards,
-John
'69 Lotus Elan S4 DHC #45/8290
'74 1/2 Jensen Healey #18918















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S4 micro switches & grounds

PostPosted: Mon Sep 17, 2001 7:00 pm
by "Carl Noble"
I realize that. And the door opening switches that turn on the courtesy
lights (none on the convert). Interesting, but I'm still at a loss how a
switch in the ground side is any better than having it on the hot side of
the device. I know that I'm missing something, because several have
mentioned that it is an ideal way to turn on something when there is a
failure.

I thought with my 99 IQ and some thinking I could figger it out. What's
blocking me is that I see a symmetric situation. Hot side -- device--cold
side(ground). Theoretically I should be able to put a switch (of fuse) on
either side. I thought that the main reason not to switch to ground is that
the typical short problem is a short to ground which shows up as a normal
condition.

Still thinking.

Carl


----- Original Message -----
From: "Roger Sieling" <***@***.***>
; <***@***.***>
Sent: Monday, September 17, 2001 7:19 AM
Subject: Re: [LotusElan.net] S4 micro switches & grounds


Actually, there's another grounding switch right under your nose in the
center of the wheel. Push it and you should hear a pair of clear hooters.

Roger


Carl-

You could certainly do this (remove the microswitch that makes/breaks the
ground to
the relay) and it would function just fine electrically.

I chose to restore my S4 to include the microswitches. Yes, it's plural on
my car
because mine predates the "fail-safe" vacuum mechanism, so my switches are
on the
headlight pods. One on the right-hand pod functions as yours on the vacuum
switch,
the other on the LH side supports the headlight flasher relay.

One reason I chose to restore mine was to insure the headlights would not
light up
while still retracted. If I turn them on before raising them, only my side
lights,
parking lights and tail lights illuminate. The headlights come on only
if/when I
raise them.

Conversely, if I raise them without first turning them on, the second
microswitch
completes the ground to the flasher relay and the headlights flash like
crazy. Not
terribly useful, but it's original and enough of an anachronism that I
wanted to
preserve it.

Finally, don't condemn all switches in the ground circuit. They're actually
quite
acceptable and used widely. Just two quick examples: That's what allows
your wipers
to "self-park" and also how both your door microswitches and you dash switch
are both
able to operate your interior lights.

In essence, multiple switches to ground allow any single one of them to make
and
complete the circuit. (Yes, there's a second ground switch directly in the
wiper
mechanism that's open when parked and closed during a "sweep")

In short, do as you see fit's your car and your situation. However, once
understood,
these ground switches are actually quite useful!

Regards,
-John
'69 Lotus Elan S4 DHC #45/8290
'74 1/2 Jensen Healey #18918









reserved.






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S4 micro switches & grounds

PostPosted: Tue Sep 18, 2001 3:42 am
by mageiger at worldnet.att.
Carl,

<Interesting, but I'm still at a loss how a switch in the ground side
is any better than having it on the hot side of the device.>

A switch on the ground side won't cause a short if grounded. The
device will simply activate.

Mike Geiger
66 Elan S3 Coupe'
78 Esprit S1

S4 micro switches & grounds

PostPosted: Tue Sep 18, 2001 4:18 am
by rodney
Carl

You are quite right having the switch on either side makes no difference, it
is still a connection that allows current (the most important thing) to
flow.

If you have one device that can be switched on by a number of switches (and
on non plastic cars these are usually very close to a convenient ground)
then you supply the hot side to the device and the cold side to any number
of switches. The other way is that you have to supply a hot wire to places
that you may not want power supplied to all the time. Remember that shorting
an earth wire to earth has very little effect, shorting an active wire to
earth can mean one cooked Lotus, so the less active wires running around the
better.

Rod

Rodney Stevens
CSIRO Minerals
http://www.minerals.csiro.au

Ph. 61 2 97106701
Fax 61 2 97106789

Personal Home Page
http://sites.netscape.net/rodjohnstevens

-----Original Message-----
From: Carl Noble [mailto:***@***.***
Sent: Tuesday, 18 September 2001 2:20 AM
To: ***@***.***
Subject: Re: [LotusElan.net] S4 micro switches & grounds


I realize that. And the door opening switches that turn on the courtesy
lights (none on the convert). Interesting, but I'm still at a loss how a
switch in the ground side is any better than having it on the hot side of
the device. I know that I'm missing something, because several have
mentioned that it is an ideal way to turn on something when there is a
failure.

I thought with my 99 IQ and some thinking I could figger it out. What's
blocking me is that I see a symmetric situation. Hot side -- device--cold
side(ground). Theoretically I should be able to put a switch (of fuse) on
either side. I thought that the main reason not to switch to ground is that
the typical short problem is a short to ground which shows up as a normal
condition.

Still thinking.

Carl


----- Original Message -----
From: "Roger Sieling" <***@***.***>
; <***@***.***>
Sent: Monday, September 17, 2001 7:19 AM
Subject: Re: [LotusElan.net] S4 micro switches & grounds


Actually, there's another grounding switch right under your nose in the
center of the wheel. Push it and you should hear a pair of clear hooters.

Roger


Carl-

You could certainly do this (remove the microswitch that makes/breaks the
ground to
the relay) and it would function just fine electrically.

I chose to restore my S4 to include the microswitches. Yes, it's plural on
my car
because mine predates the "fail-safe" vacuum mechanism, so my switches are
on the
headlight pods. One on the right-hand pod functions as yours on the vacuum
switch,
the other on the LH side supports the headlight flasher relay.

One reason I chose to restore mine was to insure the headlights would not
light up
while still retracted. If I turn them on before raising them, only my side
lights,
parking lights and tail lights illuminate. The headlights come on only
if/when I
raise them.

Conversely, if I raise them without first turning them on, the second
microswitch
completes the ground to the flasher relay and the headlights flash like
crazy. Not
terribly useful, but it's original and enough of an anachronism that I
wanted to
preserve it.

Finally, don't condemn all switches in the ground circuit. They're actually
quite
acceptable and used widely. Just two quick examples: That's what allows
your wipers
to "self-park" and also how both your door microswitches and you dash switch
are both
able to operate your interior lights.

In essence, multiple switches to ground allow any single one of them to make
and
complete the circuit. (Yes, there's a second ground switch directly in the
wiper
mechanism that's open when parked and closed during a "sweep")

In short, do as you see fit's your car and your situation. However, once
understood,
these ground switches are actually quite useful!

Regards,
-John
'69 Lotus Elan S4 DHC #45/8290
'74 1/2 Jensen Healey #18918









reserved.






*
*********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.

This footnote also confirms that this email message has been swept by
MIMEsweeper for the presence of computer viruses.


**********************************************************************











reserved.















reserved.





S4 micro switches & grounds

PostPosted: Tue Sep 18, 2001 4:49 am
by lotusnut
Hang in there Carl,
We'll get through this!
As I see it,
Lotus doors and horn: battery---fuse---device---switch---ground
Carl's proposal: battery---fuse---switch---device---ground
Don't ever: battery---switch---fuse or battery---device---fuse (a short
could cause a fire!)

If you are grounded and touch the live side of the switch the horn/light
will work but you won't notice since you are likely screaming. However you
will be passing less juice than Carl's approach because the horn is using
some. don't try this at home!

Advantage of the Lotus approach: convience, less wire to run
Disadvantage: A short between the horn and switch will activate the horn,
you will have to pull the wire off the horn. Seen it happen. Switches
tend to fail "open" not closed. Wires tend to ground out. The courtesy
lights could come on and stay on due to a shorted wire thus running down
your battery. Carl's way, you have to leave the door open.

To wire the horn Carl's way will take some thought and could be patentable.
A rotating live switch insulated from the steering column.

BTW, I fix buildings and once got zapped screwing in a light bulb while
standing on a ladder. (no joke!)
The I.P.T. (Idiotic Previous Technician) had the hot and ground leads
switched so the bulb worked but the juice was on the bulb's screw thread
and the ground was on the center.

Beware!

At 10:19 AM 9/17/01 -0500, you wrote:


S4 micro switches & grounds

PostPosted: Tue Sep 18, 2001 4:50 am
by lotusnut
Hang in there Carl,
We'll get through this!
As I see it,
Lotus doors and horn: battery---fuse---device---switch---ground
Carl's proposal: battery---fuse---switch---device---ground
Don't ever: battery---switch---fuse or battery---device---fuse (a short
could cause a fire!)

If you are grounded and touch the live side of the switch the horn/light
will work but you won't notice since you are likely screaming. However you
will be passing less juice than Carl's approach because the horn is using
some. don't try this at home!

Advantage of the Lotus approach: convience, less wire to run
Disadvantage: A short between the horn and switch will activate the horn,
you will have to pull the wire off the horn. Seen it happen. Switches
tend to fail "open" not closed. Wires tend to ground out. The courtesy
lights could come on and stay on due to a shorted wire thus running down
your battery. Carl's way, you have to leave the door open.

To wire the horn Carl's way will take some thought and could be patentable.
A rotating live switch insulated from the steering column.

BTW, I fix buildings and once got zapped screwing in a light bulb while
standing on a ladder. (no joke!)
The I.P.T. (Idiotic Previous Technician) had the hot and ground leads
switched so the bulb worked but the juice was on the bulb's screw thread
and the ground was on the center.

Beware!

At 10:19 AM 9/17/01 -0500, you wrote:


S4 micro switches & grounds

PostPosted: Tue Sep 18, 2001 6:44 am
by Lawrence King
Hi Carl:

In a Lotus you are correct doesn't matter if you switch the hot side
or the cold side. Unfortunately all of the off the shelf items used in
the Lotus were designed for cars with all metal bodies.

In a all metal car switching the cold side means that you don't need
to run a return wire, just attach the switch straight to the body.
Hope this reduces your confusion.

-Lawrence-

Carl Noble wrote:

--
Lawrence King Ottawa Ontario Canada
mailto:***@***.***

S4 micro switches & grounds

PostPosted: Tue Sep 18, 2001 10:08 pm
by Rob_LaMoreaux
Thinking about this, it probably would be ok to switch the power going to
the headlight dip switch and then ground the relays, but I don't think it
would buy you anything. You loose only one connector (black and blue wire
from relays to headlight switch where the underbonnet loom meets the dash
loom). You still have the headlight switch but now the routing would be:
power - fuse - headlight switch - dip switch - relay (hi or low) - ground.
Instead of Power - Fuse - dip switch - relay (hi or low) - headlight switch
- ground. The amount of wire eliminated is not a lot, and the main
reliablility issue is the connectors not the wire. The switches generally
don't fail so much as the connection to them and ground, and besides the
microswitches are cheap (<$3US for a good one).

I guess most of us are more concerned about losing vacuum on the headlight
switch than the electrical side of the switch.


Rob LaMoreaux
Ann Arbor, MI 48108-1273
Home: 734-971-5583
Work: 734-822-9696
Fax: 734-973-1103
Home email: ***@***.***
Work email: ***@***.***
Too many Hobbies.... Too Little Time
1969 Lotus Elan....It's not a restoration, it's a never-ending adventure.

S4 micro switches & grounds

PostPosted: Wed Sep 19, 2001 1:28 pm
by Keith Scarfe
--- In lotuselan@y..., "Roger Sieling" <rogsie@t...> wrote:

hooters.


and I thought 'a pair of hooters' meant something completely
different in the American language. ;-)

S4 micro switches & grounds

PostPosted: Wed Sep 19, 2001 1:36 pm
by "Carl Noble"
I think the adjective "clear" separates his meaning from the "usual'. :-)

Cheers,

Carl
----- Original Message -----


Sent: Wednesday, September 19, 2001 8:28 AM
Subject: [LotusElan.net] Re: S4 micro switches & grounds


--- In lotuselan@y..., "Roger Sieling" <rogsie@t...> wrote:

hooters.


and I thought 'a pair of hooters' meant something completely
different in the American language. ;-)








reserved.