Heated Seat controls

Retrofits Done Right: Physical Controls For Heated Seats

November 24, 2025 by 37 Comments

We’ve all owned something where one tiny detail drives us nuts: a blinding power LED, buttons in the wrong order, or a beep that could wake the dead. This beautifully documented project fixes exactly that kind of annoyance, only this time it’s the climate-controlled seats in a 2020 Ram 1500.

[projectsinmotion] wasn’t satisfied with adjusting seat heating and ventilation only through the truck’s touchscreen. Instead, they added real physical buttons that feel just like factory equipment. The challenge? Modern vehicles control seats through the Body Control Module (BCM) over a mix of CAN and LIN buses. To pull this off, they used an ESP32-S3 board with both CAN and LIN transceivers that sits in the middle and translates button presses into the exact messages the BCM expects.

The ESP32 also listens to the CAN bus so the new physical buttons always match whatever setting was last chosen on the touchscreen, no mismatched states, no surprises. On the mechanical side, there are 3D-printed button bezels that snap into blank switch plates that come out looking completely stock, plus a tidy enclosure for the ESP32 board itself. Wiring is fully reversible: custom adapters plug straight into the factory harness. Every pinout, every connector, and every wire color is documented with WireVis diagrams we’ve covered before, making this an easily repeatable seat-hack should you have a similar vehicle. Big thanks to [Tim] for the tip! Be sure to check out some of our other car hacks turning a mass produced item into one of a kind.

A Simple Web-Based Wiring Harness Tool

July 15, 2022 by 33 Comments

When building electronic assemblies there is quite often the need to construct custom cables to hook things up. It’s all very well if you’re prototyping by hand, or just building one or two of a thing, but if you’re cranking them out using outside help, then you’re going to want to ensure that cable is described very accurately. [Christian Nimako-Boateng Jr.] presents for us the first version of wirely, a wiring harness tool. This is a web-based tool that allows one to describe the cable ends and connectivity between them, producing a handy graphic and exports to excel in a format that should be easy to follow.

Based around the wireviz Python library running on a flask-based backend, image data are sent to the web assembly front-end and rendered with OpenGL. Configuration files can be imported and exported as JSON, making it easily linkable to other tools if required. Helpfully, the tool also seems to support some kind of revision control, although we didn’t try that yet. The process is straightforward enough, one simply defines a few groups (these relate to individual PCBs or other floating items in the assembly) which each contain one or more connectors. First, the connectors are described with part numbers, and wire gauge data, before defining the list of connections (wires) showing which signal and physical pins are connected together. Nothing more complex than that yet. We think there is still some more functionality that the tool could manage, such as shielding and guarding details, twisted pair definitions and a few others, but for a first pass, wirely looks pretty handy.

If you want a more heavyweight option using IEC 60617 symbols for describing wiring harnesses, then look no farther than QElectroTech, and yes, we have covered wireviz before, just for those that want to cut out the middleman and describe their cables in Python directly.

An Open Source Tool To Document Your Wiring

June 23, 2020 by 29 Comments

Most of us are familiar with the tools available to create circuit diagrams, as generally that’s the first step towards producing a custom PCB. But that about the cables and wiring harnesses that don’t live on your board? How do you easily document the rat’s nest perfectly logical wiring of your latest and greatest creation?

That’s precisely the question that led [Daniel Rojas] to create WireViz. This open source Python tool takes human readable input files and turns them into attractive and functional visualizations of where all the wires in your project are going. It can even be used to generate a Bill of Materials that documents the lengths of wire required and types of connectors needed to hook everything up.

If you’re still using pre-made cables to connect all of your components together, than you might not immediately see the benefit of a tool like this. But as we’ve talked about in the past, the creation of custom wiring harnesses is something that serious hardware hackers should become familiar with. Yes it takes more effort, but the end result is worth it. With a tool like WireViz, the creation of a bespoke harness for your next project just got a little bit easier.

[Daniel] has done a fantastic job documenting this project, providing not only a tutorial on how to feed and care for your WireViz, but a gallery of examples that shows off the kind of complex wiring the tool can help make sense of. But there’s plenty more to be done, and he’s happy to get feedback or code contributions from anyone who wants to get involved.