Cool turns out the AF cancelled my orders so....more time to work on the Ol beasty.

 

Another place for a pump if needed is BroncoGraveyard. That is where I got mine from when it died.

Diesel Vacuum Pump

 

DZLDenny, are you basically plugging lines leading to\fro the EGR vacum selenoid to test if it's bad or not? I have the same problem going on my 02 f250 7.3, havent checked my 4x4 but know it worked the last few times I had to lock it in. I'm also not sure about the ESOF? elec shift on fly, my truck has hubs that I manually lock in, even though it has the shift on the dash. I guess I'm asking if i need to look into that side also. I havent owned my truck too long soi I'm still learining about it I guess.

 

If you look just below where I have the lines plugged off, there is short loop of vacuum line. It has some dialectric grease on it from the battery post. This is what gave me my heater controls back. The lines I plugged off ran to the hubs. Although the lines were cracked and my heat controls weren't working, my 4x4 was. I have since put in the Warn premium hubs with my Dynatrac front end kit and these hoses are no longer serving any purpose.

I can't be sure, but I bet your truck has or had the vacuum operated hubs. Yes the 4x4 will work if you manually lock the hubs. By design, they are supposed to lock themselves with the vacuum from these lines. So just turning the dial should engage the 4x4 without you getting out to lock the hubs. Now if you or a previous owner changed out the hub to a manual hub such as the Warn or Mile Marker ect (very common because of issues with the factory set up) this would no longer be the case. There were also a few trucks that I have heard had the manual hubs from the factory, but I have never seen one. Every time someone told me they had the factory manual ones, they were the vacuum hubs. They look alike. Most times you can no longer read the "auto" or "lock" because it wears off quickly. The vacuum line on the back side of the hub gives them away.

 

DZLDenny, thanks for the pic. Couldnt believe it when I plugged those vacuum lines my dash blower started working. Picked up the solenoid today.

My truck does have the vacuum lines to the hub even though it has the manual hubs. Talked to a guy today and he said the ESOF is the dash, but the hubs lock both hubs (sort of like posse?). Eitherway that's good news for me, heck I thought I had to turn the dial and fight those stupid plastic hubs with a pair or channel locks.

Thanks a million.

 

Just a word of caution if you must use pliers to turn the hubs they are probably in need of maintenance. Mine were like this and they failed to fully lock in by ESOF and when I manually tried to lock in the hubs with pliers I broke the plastic. To make a long story short I got stuck in a feed lot and changed to Warns. Takes 30 mins.

 

Okay fellas I read this thread over and over and walked a dozen times back and fourth to my truck. Still having the ac blowing threw the defrost vents. If its possible any more ideas you can help me with before i spend money at the shop. Or if possible post more pics of certain things to check. Im fairly new to the diesel thing. Thanks guys

 

I'm certain you have a vacuum leak somewhere. If you have ESOF hubs it can be there but only if the 4WD is engaged, I had a line pop off at one of the plug/manifolds behind the glovebox that caused the system to default to defrost. Ultimately if you have no vacuum leak and vacuum pump is running it could be the diverter door actuator or the controls.

 

Thanks for your reply. My hubs are manual locking warn premiums and i have the 4x4 on the floor like the earlier year fords. I like that much better then the switch on the dash. So is it possible to start unplugging vaccum lines and be able to tell witch line has the leak?

 

Just wanted to say THANK YOU ... I upgraded my Hubs to Warner Manual and when I say this Post, I went out to my 01 F350 Diesel Super and figured the Vent action went away gradually SO after Many months of AC only from Defroster Vents ( water soaked windshield lol) I was bout to just replace the pump. Then I read your remedy and concluded that my pump was working there was suction and the tank was sealed it must be the hub solenoid stuck open... I PULLED THE TWO HOSES WITH NEEDLE NOSE AND PLUGGED WITH STUB SCRWS LIKE YOUR PICTURE TURNED OVER THE ENGINE PUT ON VENT BOOOOOM WORKING LIKE NEW !!!!!! THANK YOU THANKS YOU