94 Jimmy 4 Wheel Drive problem

I have a 94 Jimmy and when i push the button, I can hear it click, but no 4 wheel drive. I'm assuming it's the vacuum lines to the transfer case, but don't know how to test them for leaks. Is this my problem?

Check the vacuum diaphram located under the battery. They will rip and cause the 4x4 not to engage.

The vacuum actuator under the battery pulls back when the engine is running so there is good vacuum.

Could there be something wrong with the transfer case switch? Is the vacuum actuator supposed to pull the cable back even when it isn't in 4 wheel because it pulls back whenever the engine is running.
Thanks.

This has been covered a million times...:)

1st Check vac actuator under battery tray for tears, or leaks, and that the vac hose is connected. Replace if found

2nd Check vac hose leading from vac actuator to vac switch on transfer case for cracks and dry rot. Replace if found.

3rd Check remaining 2 hoses from vac switch on transfer case for dryrot or cracks Replace if found.

If all of the above are fine, disconnect your negative battery cable for 1/2 hour then reconnect it. If your 4x4 works after that you probably have a failing TCCM (Transfer case control module)

If that doesn't solve it, it's most likely the encoder motor.

if the actuator is pulling back on the cable whenever the engine is running, whether or not you have 4WD selected, the problem is the vac switch on the TC. it is stuck in the open postion. get under the vehicle, look up between the front drive shaft, and the TC, on the top you will see 3 (or sometimes only 2) vac lines going to a piece on the top of the TC. with a 7/8 wrench, romove the Vac switch, (first disconect the vac lines from it) actuall before you actually remove the switch, clean off all around it so no dirt goes into the TC. replace it with a new one, don't even bother trying to free it up with any lube, it's not worth it, if it's frozen and it pops free with some lube it will only stick again later, and you'll have to do this again.

after that is done, if your still not getting you front axle to lock, and the actuator is working OK, check that the spring clip that hold the cable to the actuator is still there and locking the cable, you will have to have the battery, and tray right out of the vehicle to check this. push in on the actuator , and make sure the cable is moving with it, if it isn't replace the spring clip, or use some lock wire instead of the clip. If it is still not locking the front Diff, your problem lies in the front diff itself, either the spring clip on the diff end of the cable, or worn components in the diff. with my 94 jimmy , I found all these problems , in the diff I had a worn thrust washer behind the locking gear on the pass side axle housing, which had led to a worn lock fork.

Hope all this helps, if you have any more questions, post again, as I have had all the "unusual" problem , and none of the "known" problems with my 4wd

Hey I have a 91 Jimmy and the front wheels wont lock up for me , i have found that the cble going into the diff will not pull out to lock it in , soo does anyone happen to know what the problem would be???? Thanks

Hey I have a 91 Jimmy and the front wheels wont lock up for me , i have found that the cble going into the diff will not pull out to lock it in , soo does anyone happen to know what the problem would be???? Thanks

See thge steps above for diagnosis