I’m in need of a latching circuit to activate a light on my dash from a momentary ground signal.

Here’s what I’m attempting to do: I recently performed a 0411 ECM swap on my GMT400 Suburban. This gives me the awesome ability to tap into the newer ECM’s tow/haul mode. It’s a major reason I did the swap since I use the ‘burb to drag the family’s 24' travel trailer all over the place.

The tow/haul mode is activated by a momentary ground signal to a pin on the ECM. Simple ‘nuff. But, I want to hook up a light to let me know that T/H mode is activated... I’m just not sure what the easiest/most cost effective means of accomplishing this would be.

So, how do I make a momentary ground into a constant 12v+ that energizes and de-energizes with each subsequent push of the button?