Norcold N611 12V Upgrade Status LEDs
After upgrading my Norcold N611 fridge – ripping out the old absorption system and replacing it with a modern 12V compressor – I ran into a small but annoying issue: no more outside controls or status LEDs.
Norcold N611 12V Upgrade: Bringing Back the Status LEDs
That’s because the original Norcold display board was bypassed in favor of a new internal controller provided with the compressor kit. While the setup works great overall, it introduced a real usability problem. The new compressor is so quiet, you can’t tell if it’s running. Worse, if the 12V supply drops (say, due to a blown fuse), the fridge silently shuts down with zero indication. Not ideal when you’re relying on it in the heat of summer.
I figured I’d try to get the old Norcold status LED working again. So, I reached out to Norcold. Unsurprisingly, true to their reputation, they didn’t respond. RC-Refrigeration – the maker of the 12V compressor upgrade – wasn’t much more helpful.
I still had a bunch of wires left behind after removing the old propane control board, and I was hoping to repurpose some of them. But I hit a roadblock: how do you know when the compressor is actually running? There’s no switched output signal from the new controller, and I wasn’t about to crack open a brand-new control box just to tap a wire.
Time to hack it myself.
I popped open the original Norcold display panel inside the fridge and swapped out the old LEDs with new green and blue ones, each paired with a resistor to safely handle 12V. From there, I traced three of the original display wires to the external fridge connector – thankfully still intact. So far, so good.
Sensing compressor activity without tapping wires: Now, back to the main challenge: how to detect whether the compressor is running, without modifying or accessing its internal wiring?
Here’s the clever part: since the compressor draws a decent amount of current while running, I simply coiled the power supply cable a few times and inserted a reed switch into the loop. The magnetic field from the current flow is enough to trip the reed switch, which in turn activates the blue “Compressor running” LED.
Simple. Reliable. Non-invasive. And it worked perfectly.
With the concept proven, all that was left was to tidy up the wiring, re-mount the old Norcold display panel with new LEDs, and get everything buttoned up. Now, I have clear visual feedback when the compressor is on—and I’ll know immediately if there’s a power issue.
Michaela Merz is an entrepreneur and first generation hacker. Her career started even before the Internet was available. She invented and developed a number of technologies now considered to be standard in modern web-environments. She is a software engineer, a Wilderness Rescue volunteer, an Advanced Emergency Medical Technician, a FAA Part 61 (PPL , IFR) , Part 107 certified UAS pilot and a licensed ham . More about Michaela ..