So here's something interesting.
My Rubi won't engage the front locker. the rear locker engages fine the but the FRONT LOCK light just keeps blinking and nothing happens. No compressor sounds either but I haven't crawled underneath yet while trying to turn it on.
Whenever I'm in 4HI or 4LO the front end just doesn't want to go if I turn the wheels too much. There's a LOT of resistance and the Jeep will slow or stop if I'm rolling. If I give it some gas while turning one of the wheels will spin, though I don't recall if it was inner or outer. Otherwise driving straight on in 4WD is no problem.
In 2HI nothing goes wrong at all. No resistance and turning is a breeze.
My crazy notion is that the front locker is actually somehow stuck engaged. I can't explain why it wouldn't still be locked in 2HI but I can't really think of any other explanation.
I could also be crazy and this could all be normal operation with the front end when in 4WD with front lockers. My last Jeep had no lockers and did not react this way in 4WD.