How to Access CHMSL Circuit on 2020 Ram 2500 Power Wagon

Updated 04/16/2021 | Published 04/14/2021

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Question:

Is the a handy pigtail within the wiring harness on my 2020 Power wagon for my canopy third brake light?

asked by: Roy

Expert Reply:

The circuit you're looking to access is known as the CHMSL (center high mounted stop lamp). I've looked through the forums, and saw several folks mention that there should be a white wire with a purple stripe buried in the harness than runs along the passenger side frame rail. Barring that, the easiest place to access that circuit would be at the 3rd stop lamp atop the back of the cab.

The # 118384 would access the brake lamp circuit for you, but the turn signal is also carried on that circuit so your 3rd brake lamp on your camper shell (which I assume is why you're looking for this circuit) would also flash with the turn signals. If the 3rd brake lamp on your camper shell is NOT an LED, you could use the # 118384, but you'd need to wire a # 118158 into the green and yellow wires from the # 118384 and use the red output wire for your camper shell. The output green and yellow wires wouldn't be needed and could be capped off. If your camper shell 3rd brake lamp is LED, you'd need to use one of the other methods described above.

expert reply by: Mike L