RFW light on 2007 Ranger comes on when not in 4 wheel drive

SOURCE: 4 wheel drive

there is a way to do that.....all you have to do is go get the manual locking hubs and switch it over...not that hard....did it to a early 90s f150....pretty easy.

SOURCE: part time light on when in 2 wheel drive off when in 4 wheel driv

I have a 2002 Jeep Liberty I had the same, there's a switch underneath the vehicle for the cable near the 4 wheel drive shaft, I had a transmission shop replace mine and that took care of the problem, I think the total cost was about $120.00 but that included labor.

Will

SOURCE: 1987 Ford Ranger stuck in 4 wheel drive!!

Chances are the linkage for the transfer case is out of adjustment try loosening the adjuster bolt and put the 4WD shifter into the position 4WD high or low (depending upon which position it's lockup in) then lock down the adjuster bolt, try to shift out of 4wd sometimes you need to go forward and backward with the vehicle to get it out of 4wd, when you get it out of 4wd you may have to fine tune the adjustment to get it to engage and disengage smoothly it's a trial and error thing keep resetting adjuster until you get the desired effect.

SOURCE: 4 wheel drive doesnt work.

Has this Jeep been modified at all?
It sounds like the shifter cable was reinstalled backwards.
Specifically the 4-Low "Not Climbing Well". 4-Low should give you the best torque and hill climbing ability.
Do you feel any "Binding" in the steering wheel (difficult to turn)?
Remember a Jeep uses real driveshafts and differentials to give you 4WD - you cannot engage 4WD or 4-Low on dry hard surfaces. It needs a little bit of slip between the wheels for turns.
Check you're fluids too.

SOURCE: need vacuum diagram for 4-wheel drive

the 4x4 don't use vacuum. the front is auto lock when the transfer is engauged with the button. if the light don't which when pressed into 4hi or 4low. the motor on the transfer case maybe hung up. they have to be used at least 4 times a year not to go bad. the motor is on the back side of the transfer case. best of luck.