does anyone have any idea what causes the 4wd not to work the relay for the 4wd clicks when the transfer is put into 4 hi but no light and no front dif movement?

Year? Model? Type?

He's got a '92 4Runner.

Well without hearing anything more, I think it sounds like you 4wd is broken. Could be your ADD went out, since that is where the litlle 4WD light comes from (there's an electrical plug on the front of your diff, I think it's what "determines" if you're 4x4 or not.)

Is your front driveshaft moving when you're in 4x4, or not. If it does move but your front wheels don't, I think your ADD needs work. MAybe a vacuum hose went bad or something (if you're lucky).

I had the same problem when they did my lift they just forgot to plug somethng back in that acctivated the add when the 4wd was engaged.

There ar 2 vacuum hoses on the front of the ADD actuator. If you put vacuum on the one closest to the diff it should activate the front hub.

what is the relay in the dash that clicks when the transfer is out into 4WD? I keep hearing it .thanks for the info will try to get at this weekend.

the relay is activating the vacuum solenoids for the ADD, or at least trying to.

When I bought my runner the 4 wheel drive didnt work got it for a good price
layed under the tranny noticed a plug just hanging around. Once I found its home the 4 wheel light in the cab came on and everything locked in.
good luck finding your prob. let us know

found the problem, the dumb @$$ that had it before replaced the heasd and crossed the vac.lines the activate the add thanks to evreyone for the helpful input, very useful.