Hi I'm new to the forum, I've looked at a lot of posts trying to figure this out but I'm not seeing what I need.

I lost one of the vacuum hubs which is fine I decided to go with manual lock. An easy change out. What my question is basically is if the vacuum lines are still needed. Reason I asked , I had a problem with my heater/ac quitting blowing frequently. I capped the vacuum line where it tees off to go to the 4wd controls and the problem went away. Now I just installed the manual hubs and the 4wd doesn't appear to be working. The switch still shifts the transfer case into low and high 4wd but the wheels don't seem to be locking in.

Thanks

 

Welcome to the forum

1998 to 2000 Rangers used PVH(pulse vacuum hubs), a bad idea Ford abandoned only after a few years.

AVM rugged ridge are the only manual hubs made for these I think.

Article here on the conversion: 1998-2000 Ford Ranger Rugged Ridge (AVM) Locking Hubs

Yes, the PVH hubs got their vacuum from the vacuum reservoir so those hoses need to be plugged or capped, or it will effect Climate Controls which also uses the same vacuum reservoir.

When you manually lock the hubs then front drive shaft should turn even when you are in 2WD.
Can you check that, have someone look while you roll truck forward or backward.

If the shift motor is working then all is well with the system.
The manual hubs may not be working if you don't feel a pulling in the steering wheel when turning in 4WD

If locking manual hubs make front drive shaft turn in 2WD and shift motor is working but still no 4WD then problem is in the transfer case
Leave manual hubs unlocked, jack up rear wheels and shift into 4WD high, put in gear and see if front drive shaft turns when rear drive shaft does