arsenuts411

I have a 2004 f150 with the 5.4 and 4 wheel drive is not engaging. I just replace the iwe solenoid to the upgrade style with the cover so water is not dripping right on the solenoid. I noticed that there there is no vacuum in the line where engine feeds the solenoid. My question is how do I access that vacuum line? I see it goes to the back of the engine do I have to remove the intake? I want to check and see if there is any cracks in that line because I am not getting any vacuum to solenoid.

Simpleaim

I may be wrong but I think if you don't have any vacuum the 4wd will engage. I think the vacuum keeps it from engaging.

DarrinT04

You are correct. When the truck is in 2wd, the iwe solenoid is open to allow vacuum to the actuators to hold them released. Switch to 4wd, the solenoid blocks off vacuum and the actuators lock to the axle. In your case, I would first start by checking the 2 check valves on the vacuum line. If they are original I would go ahead and replace them. They are cheap and easy. Just pull the vacuum line off each end of the check valve and put new ones in place. When I bought my truck, one of the check valves were so clogged with dirt that no vacuum could pass through. Hubs were locked tight and wouldnt release. I replaced the check valve and the other one too but it wasn't clogged with dirt. Hubs were still locked. Had to replace both actuators. They were pretty badly damaged from being locked for a long time. I replaced the iwe solenoid while there too. My 4wd works properly now

isvend

When I bought mine that vacuum line was pinched behind the intake, I had to remove the intake to straighten it out. I found that there were clips that looked like they were meant to hold that vacuum line above the intake and ran it along those. If you pull the intake just make sure the IMRC mounted to the back of it doesn't get caught up on any wires or anything when putting it back on, it's soooo close to the firewall that those arms get stuck easily.

ANDREWROBISON

I just replaced all of my front end and my 4 wheel drive wasn't working before because of the actuators, how can I make sure the new ones are working right? start the truck and jack up the wheel and see if the cv spins with it?

dukedkt442

That’s probably the easiest way. The axle shouldn’t move at all when spinning the wheel.

Ford_Dude_863

I don’t get any vacuum from my upper port of the solenoid for my 2019 Ford F-150 while I’m engaged in 2wd? Anybody know why?

redfishtd

A 2019 vehicle is Greek to us . Our vacuum comes off a metal wye by the brake booster . The 2004 came off the rear of the intake and was a bear to get it reinserted because it was so tight clearances . 05 and up intake manifolds plugged that rear vac connection , so you had to drill it out to use it on 04 .
If you cant follow it maybe a youtube diy smoke machine will find the open leak .