How can i turn a DPST button in to a DPDT?

I've replaced all the stock rocker switches in UTV, got all 14 of them done except for one all to Push Buttons. The push buttons are SPDT, "on/on" NC and NO, rated to 5 A. (billetautomotivebuttions.com 22mm)

To get the light to engage with the button, you wire the positive or negative switching, and run it through the light. It works fine for 12 V relays and normal functions, and for the rest of the button locations.

I ran in to an issue. There is a button that goes to the ECU, it is a over ride function, negating the rev limiter to a higher preset, for launch control. This was a kit they had, and as an oversight, the stock rocker was a DPDT switch to achieve this.

It has a 3.3 V to the switch (override), a common GND back to the ECU, and the other lead is 12 V (normal), a same common GND back to the ECU.

I can wire this with one of the NC and NO contacts, and I can get the function to engage on the cluster correctly, on and off no problem, but I can not get the light to engage when on. If i wire the indicator led to the loop, a few things happen,

  1. If I wire the light after engagement, I get override and a faint light, (3.3 V instead of 12 V).

  2. In that same setup, if I engage and disengage the button, the light will come on but cancels out and doesn't engage the override function.

  3. If I wire it to ACC, or the other lead, I can get a light on when off, or light on all the time scenario (duh - right? lol).

So I figured I would try a small 3 V trigger relay, so I can get it to engage the relay when the circuit is connected, and engage the indicator light. Well they all use the same GND ultimately, and I get a light on all the time scenario :(

And they don't make a DPDT button like the other ones to match the panel.

I am getting frustrated because other than the light, the rest of this install is complete, and I'm a few weeks behind.

Any ideas? (They do not make a DPDT button to match the rest in the cluster ...)

Thank you.

Ultimately trying to figure how I should wire the image in the lower right corner? Or if there is a better way to achieve this desired outcome?

here is the schematic form the manual on the UTV, and my botched attempt w the relay that did not work

  • \$\begingroup\$ Vince, I've done a big clean-up on your question. You need to capitalise properly for legibility and clarity. If English isn't your first language then please mention that in your user profile. Can you edit to make clear what the real question is? Maybe a one-line summary at the bottom. \$\endgroup\$
    – Transistor
    Commented May 7, 2021 at 20:31
  • \$\begingroup\$ English is my first language, however it is not my strong point and i have fat thumbs... I do apologize. ultimately trying to figure how I should wire the image in the lower right corner? or if there is a better way to achieve this desired outcome? \$\endgroup\$ Commented May 7, 2021 at 20:34
  • \$\begingroup\$ I'm not following the schematic you drew in the bottom right. Is that relay upside down? \$\endgroup\$
    – Hearth
    Commented May 7, 2021 at 20:40
  • \$\begingroup\$ yes, it was just a quick representation, or an attempt anyways. \$\endgroup\$ Commented May 7, 2021 at 20:41
  • \$\begingroup\$ i could not find a NC NO DTST image, so what's shown in the dashed line box is the function of the latching push button. the led I'm trying to engage is also with in the button, but has + and - leads that you tie in with the function, i was trying to get the relay to engage the light when engaged, i really wished they had just made a DPDT button in the same style, as it would solve this issue, but there has to be a work around, that is hopefully not a rube Goldberg machine. \$\endgroup\$ Commented May 7, 2021 at 20:45

1 Answer 1


Here is the equivalent circuit of the original switch, ignoring any presumptions about what it is connected to:-


simulate this circuit – Schematic created using CircuitLab

To reproduce its functionality with a single-throw switch and relay, do this:-


simulate this circuit

Diode D2 (which can be any general purpose type such as 1N4001) is required if the relay does not have a diode built in. It prevents switch contact arcing and EMI which would otherwise be caused by back-emf generated by the relay coil when it is switched off.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.