My B2 easily goes into 4wd high but not so much with 4wd low. The low light just flashes and doesn't engage 4wd low. Strangely though, if I shut off the engine and turn the ignition on, it engages the 4wd low. However, I then need to turn the motor off to disengage 4wd low. Anyone have any idea what's causing this? Thinking it may be a faulty sensor, but aren't the same sensors needed for 4wd high?