I was thinking about purchasing another DSC switch to turn on & off a small fan (2-3 amps).
I have two spare slots on the dash that would nice to use
Is is suitable for this application?
I don't want a momentary action switch; however, a on light would be nice
Is a relay needed?
Thanks for your input.

 

somebody has to be first; let us know what happens.
.

 

I'm sure the switch is rated for that amperage as most aftermarket switches are rated for 25A. There are a couple ways to wire this I would imagine you would want to switch the positive leg, a single pole single throw SPST switch would work as long as the loads are wired in parallel. Without seeing the wiring diagram or metering out the switch I don't know what kind of switch it is, maybe a SPDT?

https://www.texasindustrialelectric.com/switches.asp

I like 58328-100 with the pilot light, you want the dependent ground so the light illuminates when you activate the switch, this will be cleaner than the dsc switch and trying to add a light somewhere, and the wiring is far simpler. Looks like it would fit where the dsc switch goes, these must be standardized sizes I would guess.

 

The DSC switch is a just an illuminated momentary switch.
To use a factory DSC switch to turn a fan on/off you'd need to use a bi-stable relay circuit like one of these: In this case the DSC momentary switch is used to send a ground pulse to the signal pin which triggers the state change(off>on, on>off) of the circuit's relay.
These are only rated to 10 amps so if your fan draws >8 amps you'll need a second relay that can handle the higher current to power your device. The bi-stable relay output would be used to trigger a normal DPST relay.
You can use the switches' illumination to indicate on/off status by using the diagram below.

 

Thanks Stubbs that was my concern.
I got a new DSC switch going cheap btw.
I will go aftermarket. Thanks for the link SleepeR1st.
What I ready would like to set up is an HOA switch (Hand, Off, Automatic)
This would allow for thermostat control or have the fan on all the time.
Very common in the HVAC industry.

 

yeah, I was just going to say the same thing; likely just sends a signal rather than latching on/off.
.

 

So you want fan on, fan off, and fan auto? You want to have the ability to leave the fan shut off in the third switch position?

I think you might want an SPDT switch 58328-103 if you actually want to switch between fan on, and fan auto.

If you want the first one maybe you need a triple throw switch with one of the contacts wired to nothing to deactivate the fan.

 

he wants an OE switch to fit in the existing dash accessory opening. Maybe something like the fog light switch or similar is latching.

 

I'd be willing to bet the above ones I mentioned will fit, but I don't have access to my switches right now to pull them out and measure to ensure fit. It states its a 1.48" x 0.83" Rectangular Hole snap in panel mount, with my calibrated eyeball it looks like it would fit fine. They are cheap enough that I would buy it anyways to test fit, it would provide the cleanest install without needing to label another rx8 switch, but that's just me,

 

The switch may be the least of my worries.
I temporarily used a fuse holder as a switch.
I do expect some laughs btw.
In my defense the bilge blower (zip tied to the brace) and vent hose came from a marine store and are used for removing gas vapors.
Anyhow the Adaptronic ecu did get warm and went into "limp mode" even with a good amount of air movement in the enclosure.
Hose was routed so that it did not fold over on itself.
It was a 95+ degree day yesterday in the DMV.
I iced down the enclosure with good success.
Did not have to drive back to Baltimore with no power steering again.
Worried about frying my output drivers again.
Probably should move this post right

 

Interesting! So you're just using this to run a fan for your ECU?

 

The DSC "switch" is just a button, so further signal processing is necessary to get a second one to act as a switch.

Personally, I'd just cut a hole in one of the remaining accessory switch dummy blanks and mount a generic switch there. Get a black switch so it blends in; nobody will know it's not stock.

 

Yep I use the original intake and exhaust as both intake.
Cut away most of the internal plastic duct work.
Tried to reduce restrictions as much as possible

 

maybe you need a different hobby
.

 

Trying to engineer a solution here.
Having several ecus on the shelf is NOT the solution btw.
Just saying