The Advance Adapters RubiCrawler Control Module (SKU 42R800) is the electronic interface that lets your Rubicon's factory driveline electronics keep working the way they're supposed to once a RubiCrawler underdrive is in the mix.
Here's the problem it solves: install a RubiCrawler for a deeper low-range ratio, and the Jeep's computer doesn't know it's in "low" anymore. That means the front and rear locking differentials and, on JK models, the electronic sway bar disconnect, won't engage — because as far as the vehicle's electronics are concerned, you're still in high range. This module closes that gap. Once it's wired in and the RubiCrawler is shifted into 2.72 low, the Rubicon's electronics see it as low range and everything behaves exactly like it would in a stock transfer case — lockers engage, sway bar disconnect functions, and all the factory-programmed low-range behavior comes back online.
For JK owners specifically, there's a bonus: with the module installed, you can run the vehicle in two-wheel-drive low range and have the stability control system disable itself automatically, just as it would in a stock 4WD-low setup. That's a meaningful convenience for anyone running 2WD-low in technical terrain and not wanting to fight the traction control system the whole way.
What's included in the kit:
- Control Module, Harness Sub Assembly (42R800-A)
- Micro Fuse Harness Sub Assembly (42R800-C)
- Power Supply Wire for 42R800 Kit (42R800-E)
- Heat Shrink Butt Connectors (42R800-F)
- Heat Shrink, 2" for Fuse Tap (42R800-G)
Important wiring note: In November 2023, Advance Adapters updated the wire color coding used on the control module. Installation instructions are available for both the current and legacy color-coded kits, so double-check which version you have on hand before wiring it in — matching the correct instruction sheet to your harness's color code will save a lot of head-scratching during install.
This module is purpose-built for Rubicon owners running a RubiCrawler underdrive who don't want to give up the factory locker and sway-bar-disconnect functionality that makes the Rubicon trim worth having in the first place. Rather than losing those features once you add a deeper low range, this kit lets you keep them fully operational — so your Jeep's electronics stay in sync with what's actually happening at the transfer case, no matter which range you're crawling in.