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.
*
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