[Bounty__Hunter]

Morgster, don't forget that the YJ changed the 4wd light setup from a vacuum operated switch on the firewall to a plunger switch on the front axle disconnect. When the shift fork locks the two axle shafts together, it depresses a plunger that sends an electrical signal from the front axle to the dash light, activating the light. If the light is not on in newer YJ's, the shift fork is not moving in the front axle.



Best way to test the vacuum at the front axle, have somebody shift the transfer case from 2wd to 4wd and back while you feel for vacuum in the two lines at the front axle. Shoud be strong vacuum in one line for 2wd and the other for 4wd. If it checks out, the problem is in the shift motor bolted to the front axle (4bolts). Remove and work the shift fork by hand while spraying down with WD40. Spray in the vacuum ports real good too.[addsig]

	Transfer Case Mounted behind and driven by the vehicle transmission, the transfer case transmits power to the front and rear driveshafts in 4WD Jeep vehicles and offers high and low range.

	Front Axle Disconnect A mechanical or vacuum-operated component used primarily on four-wheel-drive models to connect and disconnect drive torque to the front axle. When shifting from four-wheel drive to two-wheel drive, this system disengages the front axle from the front driveline, so that the front wheels aren't turning the front driveline unnecessarily. This reduces unnecessary front driveline wear, noise and fuel consumption.