I lost 4wd on my 99 f-150. It has the manual shift lever.

Last year I replaced the vacuum lines running to the front differential, so the first thing I did was check those. THey are still good and it is getting vacuum to the diaphram on the differential. THe vacuum switches when the lever is engaged to 4hi. The 4x4 solenoid is working because I can hear the relay click when the lever is moved. However I still have no 4x4.

Tonight I will put the truck up on 4 jackstands and do some more checking. I noticed that there are multiple wire harnesses coming from that T-case. My Haynes manual tells me nothing so I just ordered one of those Ford factory CDROM manuals.

Any ideas on what the problem is? Also, can anybody explain exactly what happens when you pull that manual lever to 4hi? I mean, how does the 4wd activate? I am assuming the t-case is activated fully manually and the front pumpkin is engaged via the vacuum diaphram on it?

THanks,
kev

 

FIXED!

Stupid me, stupid me. I replaced the hard vacuum lines running from the solenoids to the vacuum actuator a few months ago because I noticed the one was broken (replaced with standard rubber lines). When doing this, I must have inadvertantly switched two of the lines at the one solenoid. It took me a bit to find the problem the other night but I found it.

Anyways it is fixed and cost me nothing. I wish that was the case all the time, lol.

kev

 

Hee hee... that was actually going to be my first suggestion!

Glad you got it fixed.

-Joe