I know there is a lot of threads addressing common 4X4 engagement issues and I have looked through but my situation seems different. I have a 2007 F150 FX4. When I select 4H I can hear the mechanism(hubs) clicking. When I jack the front up and turn the wheels, the shaft does turn so they do lock. It feels like it is in four wheel driving on pavement but the 4 High light does NOT come on. It might blip for a half second but not stay on. Further, if I put it in four low and back, I can hear the transfer case clunk and the four low light may come on. Ideas? Might this be just an issue with the light/switch/contacts rather than the actual system? I should add I have not had the chance to test the four wheel off road to see what the wheels do, only going by feel and what seems to be. If you know about this or a way to better diagnose, I would appreciate it.

 

Gotta to rent a vacuum pump from your local auto parts store to properly troubleshoot .. they are normally free to use.. it could be your IWE solenoid or your T-case shift motor.. from what you state. you would know if your in 4 lo for sure ... if its shifting into 4wd i would look at your solenoid..

 

From what you're describing it sounds like it is going into 4x4 with the pavement drag and the IWE's are locking as your shafts are turning as well but either the IWE Solenoid isn't providing the proper resistance value to make the computer happy or the 4x4 High/Low Indicator switch isn't reading properly. I can tell you for sure, the IWE solenoid wants to see a certain load value. I had a bad IWE Solenoid that would work but the computer wouldn't light the 4x4 indicator as the computer considers it a fault. I don't think it sounds like the shift motor but it's possible it's mis-aligning or something that the 4x4 high/low indicator sensor isn't getting a proper reading.


See the attached picture of the 4x4 High/Low Indicator, maybe it will help.

 

Thank you very much for all that info. It turns out it was just the solenoid and the issue is now resolved. I will definitely be keeping the info you provided for reference.