I have a 2010 f 250 super-duty and i cannot get vacuum past the solenoid mounted on top of the radiator. Ford has given me nothing but bad advice. I know i have a vacuum leak after the solenoid and need to replace the lines going to the two hubs but when i switch on the 4wd and hook up a vacuum gauge the vacuum is good up to the solenoid about 12 inches. i constantly have 12 volts going to the center lead but nothing else in the other two leads either in 4 high, 4 low, or 2wd. Am I missing something here? shouldn't there be a voltage change when i turn the switch to 4wd to actuate the vacuum solenoid to let the vacuum pass thru the solenoid? I have tried replacing the solenoid but that did not help.Also should i buy the vacuum line from ford at $148.00 or use rubber vacuum line and make at down to the hubs?

Thanks for any help I can get Chris

 

Once you switch the **** to 4 hi...the vacuum is only applied to the hubs for a short period of time, 20 seconds or so I think. How soon after switching the **** are you checking for vacuum post solenoid?

 

I had the vacuum gauge hooked up went into the cab turned the **** and went to the front of the cab and there was no vacuum. like i said earlier I do not think I am getting electrical power to the solenoid. When I turn the **** the 4wd light comes on if the hubs are locked manually it will shift the transfer case into 4wd, but I see no electrical change at the vacuum solenoid. nor do I ever get any vacuum thru the solenoid.
Thanks Chris

 

Chris, I have included part of the wiring diagram for my 2009, and I think your 2010 would be the same.





Pin 2 is +12V which comes from fuse 35 in the SJB at the passenger footrest. Pin 1 is for locking the hubs, and Pin 3 is unlock. These signals come from the 4X4 module and I would assume each goes to ground when activated.

According to the manual, each ground is only present for a short period of time (50 seconds to lock, and only 15 secs for unlock). During either time, some vacuum (5-9in.) will be present to the hubs.

Hope this helps. Good luck in troubleshooting.

Tom

 

Thanks Tom
I will check it out I appreciate your feedback.
Chris