Ford Superduty Vacuum hubs not engaging or disengaging. Using 2002 Ford F-250. 

For those who are curious, the vacuum solenoid can be activated to lock or unlock manually by grounding the corresponding outer terminal while 12v is applied to the center terminal. This means that if your truck doesn’t have a 4x4 control module behind the glove box you can use a momentary on-off-on rocker switch in combination with the stock vacuum solenoid to operate the vacuum hubs. The minor inconvenience of holding the momentary switch until lockup (maximum waiting time of 30-45 seconds) or holding until unlock (maximum waiting time of 10 seconds) is still faster and more convenient than getting out of the truck.

Just bought an 08 f250, first 4x4 I've ever owned. Very helpful and educational. I can only get 4x4 in manual lock out right now, so understanding the system is super helpful.

excellent walk thru of the vacuum system. Gave me all the info I needed to identify the problems with my 350. Thumbs up !

Great video! I love the detail. Was able to solve my automatic hub locking issue. Thank you for posting this video.

This is the best, most informative, detailed, intelligent instruction out there. You solved the 3 problems on my 2003 F350 6.0 diesel. Just took brakes off front driver side, took the wheel and lock out off to replace the old hub assembly but ran into a snag with the last bolt......it's stuck! Anyway, I now know all about the vacuum system etc. You really know your stuff and your explanations are down home. Thank u for that. I am a mechanics daughter, mechanics sister x3, and a mechanics niece lol. I wish I had listened and went to automotive school. I do alright for an ole' Texas gal. I'll update soon

Excellent video! Very detailed! Nice work.

Long but excellent

All the vids I have seen I am shocked I have not found your channel sooner.. Thanks for the great info .Subbed now Keep up the great work ..

Your video is very helpful Thank you for making this video

Thanks, it's a great video I have the exact same problem with my 01 f 250

I have a 2000 7.3, normally leave the hubs unlocked and just turn the switch to 4wd low to get the lower gear on the back tires to help pull a trailer up a dirt hill where it was parked, then flip the switch back and I'm on my way. Today when I switched it back, lights and all still on dash and would not disengage, after 10 times switching back and fourth it finally did, thankfully. I just had new bearings installed on front, and all new pads and rotors not long ago. Has me wondering if they messed something up or maybe that solenoid just needs to be replaced. Wish I was more mechanical minded! Any ideas right off? I'd owe ya

Having vent issues and 4x4 not engaging . And hear motor engage transfer case and light come on dash and shows 4x4 don't know whats going on .

Subbed!

Great video, learned some good info. Followed the steps you provided all checks out but still air only comes out of defrost and floor. Can you recommend any further steps? Martin

Im hunting down this same problem with my 2008. 4x4 lights come on dash when dash switch is turned. Hub locks work fine. Vacuum pump runs full time. It shuts off when nipple is covered. I pulled the lines off the solonoid and blew a lung full of vape through the line to the pump. There's smoke coming out somewhere underneath the battery tray. I pulled my drivers wheel liner and the connection at the vacuum reservoir is solid. Theres a T connection on the other side of the reservoir but i can only see it through a tiny window next to the radiatior. Im pretty sure that T or the line connections there are damaged. Im praying thats my only problem. I dont want to be dicking with the knuckle seals.

Does manually turning the hubs at the wheels over ride the vacuum operation is you are in 4x4 and cannot disengage?

Ok so if it only blows out of defrost that means I have a bad pump or bad reservoir?