Hello forum, wondering if someone could help?

I have a 2017 F150 Lariat, I have seen and read most of the topics about the IWEs partially engaging and/or not working. I recently had both IWE's replaced by the dealer under warranty. Now I have installed a 3" leveling kit and they no longer work. I know, I know, everyone has problems after installing a leveling kit. I'll will switch to the proper 4" lift as soon as I save the money.

This is where I am at: I noticed that both my front axles are turning when in 2wd, so I started checking. First I pulled the vacuum hose off at the switch on the firewall, jacked both front wheels off the ground and applied 10 lbs of vacuum with my vacuum pump. Both hubs unlocked when the vacuum was applied so I think I can assume both actuators and the vacuum lines to them are good. I then ordered a new firewall 4x4 vacuum solenoid purge valve for $16 bucks off Amazon. Thinking that this would surely fix the problem, it came in a couple days and I have changed it out. With the engine running the hubs still do not unlock. I checked the vacuum from the bottom port by disconnecting the line an putting my finger on it. It has plenty of vacuum coming from the motor, but when I plug it back into the solenoid there is no vacuum on the top port, the port that goes down to the hubs.

If I take the bottom engine vacuum line off and connect it to the line going down to the hubs they work just fine. I just went through all the fuses that I could find that mentioned anything to do with IWE or 4x4. They of course are all good.

Any thoughts?? Did I get a bad solenoid possibly, anyone have a thought about how to test the solenoid? I am going to go out now and try to check power to the solenoid. Thought I would write this quick to see if someone might have an idea or two.

Thank you,

Rick

 

OK, I guess no one has any thoughts on this issue. Thought I found a post about someone with a 2018 F150 with the same issue, in his/her last post they said they were taking it to the dealer to find the problem then nothing past that? I tried to reply to the post but got bumped off cause I couldn't remember my password, now I can't find it again. If anyone knows where to find that post please let me know. I'm not an expert on these forums by any means.

At this point I have received a replacement solenoid for my truck and installed, exactly the same problem as before, no vacuum coming through. I have been trying to test power but still working on that. I don't seem to have 12volts coming to either port on the 2 prong plug, read somewhere that the switch usese ground to change the position. I can't get it to do anything, getting ready to run a hot jumper from the battery to see if I can get it to switch.

Any help at all would be appreciated.

Thank you,

Rick

 

OK, here's more evidence. I still have no clue where to go from here.

Key on, move 4wd selector to each point. 2h 4a 4h 4l, I get an indicator on the dash that says each of them. I hooked up my code reader, there are no codes. I do have 12v going to the red/white wire, can't see any ground in black wire in any selection of the selector switch inside the cab. Any Ford Tech's on here??

I have connected the 2 vacuum lines together bypassing the solenoid for now so that my hubs stay unlocked. If I figure this out I will come back to let everyone know.

Again, any and all help would be greatly appreciated...

Rick

 

I had this problem on my 2011 F-150. I replaced both front coils and was careless / ignorant to the vacuum lines and fought the issue forever. I fought adding pieces of rubber hose all over the place to fix the leaks in the line and eventually just bought an entire new hose kit from a parts dealer. It was relatively inexpensive (around $75) and fixed the problem. Once I tore the old lines off I hooked them to a compressor and covered them in soapy water. There were tons of cracks I would never have seen while they were installed. The kit i purchased came with 2 solenoids and I purchased a third for a little over $13 to just replace that entire system. I could feel vacuum from the solenoids but decided to just do it.

I know it was an older truck but hopefully it gives you and idea of where to look next.

Have you checked to see if any of the lines are pinched or pulling to hard with the leveling kit? I know there isn't a lot of slack in the upper parts of the lines that are mounted to the frame.

Here's the kit I used for reference3 -
Good luck!

 

IWE vacuum line leaking is covered in Ford's TSB 20-2307, though lines with pinholes or cracks all over sounds unusual and likely not covered by this TSB.

 

The solenoid will not function until you have driven the truck approximately 1/2 mile. If you were to check the voltage coming into the solenoid after starting the vehicle it should read between 5.3 - 6.0 volts, with no vacuum on the bottom end. After driving the vehicle the voltage should read higher than 12 volts with vacuum on the bottom end of the solenoid.