looking for dp relay for single switch

Huw Powell human747 at attbi.com
Mon Aug 26 17:34:20 EDT 2002

> I'm gonna be buying one of those PIAA combo
> fog/driving light sets. Now, I have the single
> throw fog light button on my 200's dash. I would
> like to use this switch to operate both sides of
> the light. I would like three different modes:
> 1. fogs
> 2. driving
> 3. off
> Are there any relays out there like this that
> operate off one single throw switch?

the short answer would be "no, forget it."

If you feel like building some sort of logic circuit with several
relays, using the stock switch as a trigger for each step of the way,
you might be able to.  There will be no simple way to make a 0-1 switch
do several things without playing some fun games.

let's say you want the "cycle" to be off-fogs-driving-off, which is the
simplest and requires 3 output states - each one triggered by a
momentary activation of the dash switch.

You'll want to use double pole relays, where one pole turns on the light
in question, and the other one changes the "function" of your dash
switch, making it turn on *the other* relay.  These relays will also
have to stay "on" until instructed to turn "off", ie latching relays.
You might be able to pull this off with two of them, they are expensive
though, might be better to get a couple of low current ones and let them
trigger some simple high current SPST relays to actually run the bulbs.

probably easier to get a spare switch from a wreck and use one switch
for each function.  The 200 has some blank spaces available, right?

Huw Powell



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