4x4 Engagement Problem Fix 97 Expedition
There are lots a great posts that helped me fix this problem, thanks to all. I will summarize what I learned from these posts and what I found. I have electronic control. When I swithched to 4H or 4L, all indications were that it was working, lights, clicking, xfr case noises etc...but no front wheel power. After searching through these posts it seemed that my problem was related to the vacum control. I found the two vacum control solenoids on the upper right side of the firewall right under the hood hinge. The one with the pink hose controls 2x4, the blue hose 4x4. When the switch was cycled in and out of 4H, I could feel the solenoid action, but difficlult to tell which one (later I discovered that only the 2x4 was working) I started inspection of the vacum lines (pink & blue) down to the transfer case. With the front end on ramps I was following the lines to the fwd transfer case (the lines are routed inside black split tubing). I noticed that the tubes had been routed across the right front shaft and the coupling had grinded a hole in the blue tube(4x4). With engine running and having a helper switch to 4x4, no suction in the Blue tube, which there should be. Foud that the blue tube had sucked lots of debris and was clogged. Also found that the solenoid was clogged when I removed the lines from it. Not wanting to buy a new one, I removed the solenoid and spent some time cleaning with penatrant, blowing it out and actuatin with 12Vdc. (When looking at the contacts of the solenoid, left is 12V, right is GND). Finally cleared solenoid and reistalled. Cleared and blew out blue line down to where it was cut. Did a quick (temorary) repair of the line. Found that the insulation off of 10G electrical wire is the same size and stiffness, put this insulation between break, covered with larger tubing (from fish tank) an covered all with 3M Supper 88 Electrical (the good stuff). Fired up and all works good. Also re routed the lines so they wont get ground off again. Hope this helps.