On Thu, 26 May 1994, award winner Philip J Ethier went on and on and on
and on about snake turn signals and flashers and indicators:
[Stuff deleted]
> This is weird enough for most people.
Certainly weird enough for me! Here is what I remember from the last
time I wired a two-prong flasher unit and a single dash indicator:
One side of the flasher is fed +12 volts from the fuse block. The other
side of the flasher goes to the turn signal switch common terminal.
The left position contact of the turn signal switch goes to ALL the left
turn signals and the right position contact goes to ALL the right turn
signals. ALL turn signals are grounded through the various body parts.
Nothing weird sofar. Agree?
When you turn the turn signal switch to the right, current flows through
the battery, probably through the ignition switch, through the fuse, then
through the flasher unit, through the turn signal switch to the turn
signals, through the snake body back to the battery.
Circuit is complete, the right-turn signals come on until the current
flowing through the flasher unit heats up the little bimetallic strip
and the contact inside the flasher open up the circuit and interrupts
the current flow. This has already been covered.
Still nothing weird. Right?
Now, connect a small indicator lamp between the wire from the switch's
right turn contact and the wire from the switch's left turn contact.
When a voltage is present at the ungrounded end of the right turn signals,
current will flow through the indicator lamp, through the left turn
signals to ground. The current through this circuit is not high enough
to light the bulbs in the left turn signals, but is high enough to light
the indicator lamp on the dash.
If you are making a left turn, just substitute left for right and right
for left in the description above.
So, Roland is actually right. The turn indicator *is* in series with the
turn signals, but only with those on the 'other' side.
ASCII TURN SIGNAL WIRING DIAGRAM:
-----TURN SIGNAL-----| GROUND
|
SWITCH +-----TURN SIGNAL-----| GROUND
|
LEFT |
0---------+
|
BATTERY--FUSE--FLASHER---0 0 OFF * <-- TURN INDICATOR
| |
| 0---------+
| RIGHT |
| |
| +-----TURN SIGNAL-----| GROUND
- |
GROUND -----TURN SIGNAL-----| GROUND
-- Flemming Larsen flarsen@uclink.berkeley.edu
|