Ive been having problems with my 4 wheel drive not kicking it over the past months. I have a 97 4x4 lariat. Today I decided not to be lazy and get up under there and tinker around for a bit. Right above my transfer case I found a wire that wasnt connected to anything and also one that ran up and around my right front tire. When i put it in 4 low, i can hear the "click" underneath my truck (im asuming that its in 4 low) but I cant tell it in the mud. When I put it in 4 hi i hear nothing. Just wondering if those wires could have something to do with it, or is it low on fluid in the transfer case or what? I have NO clue what is wrong. Any help would be GREATLY appreciated!!!

 

Just a little update. I found where one of the went. Im guessing it is the vacum line. It hat a 3 prong slot that was on the end of it that went up and above the plastic guard by the wheel. However there was another line that was attached to it, that had no end on it, like it had been cut off or something is that normal. Still havent found where the wire connection goes around the transfer case/transmission.

 

Check the vacuum lines, on the front diff! Make sure they're connected. The check the vacuum lines on the accuators. They're up in the engine bay, passenger side, on the firewall, not the fender, behind the battery! There's 2 of them! See if they are hooked up! If so, check for leaks, hose breakage, rips. These accuators have a tendency of also going bad. I had the same problem, an had to replace both. I didn't have enough vacuum to either engage or disengage.

 

I got underneath and followed one of the disconnected lines up to behind the battery all the way down to the connector beside the vacuum pump by the transfer case. (one blue and one white wire, with what appears to be a suction hose.) All three of thse have been cut/melted. Does that seem like it could cause the problem? If so could I go to a junk yard and get the whole assembly (pump and hoses) and replace myself, or should I go to a dealer and have them deal with it?.

 

So Ive been under it all day, and i replaced the lines that run up to behind the battery, and it will go in low cuz i put it in low and gave it gas and it almost jumped off the ground. 4H is a diff story it wont lock in. So im gusessing rubber hose is a vent or something. Also I read that spraying wd40 on the actuators and pistons and moving them in and out should work..... where are the pistons and actuators?

 

U and I I think are having the same issue. 4L works right but no 4H.
Does your light come on for 4H when you select it or do you just hear clicking sounds under the oval in the passenger side dash with no light?