Your relays aren't getting power. I have a extra 4x4 switch so I checked my readings
The switch has have numbers 1-2-3-4 inside the socket at the little prongs/fingers
Between 1-4 I get 19.2 ohms
Between 2-3 I get 130.7 ohms
There is a little circuit board inside you can barely see. There are three clips holding the backing plate. Pop that plate see if that board got smoked.

Let me know what prongs you're checking and I'll check my readings against yours

 

When I check the switch itself for continuity, I only get a reading on the middle 2 prongs.
In 2wd I get a 3.9 ohms
In 4Hi I get a 1.10 ohms
In 4Lo I get a 0.45 ohms

I did a little more research and found that to be normal and within spec.

I'm starting to lean towards this being a VSM module. According to my research that is what controls the electronic 4x4, am I right?

What steps should I take to go about replacing that...? I can replace it myself... Supposedly it's located on the passenger side behind the glove box, easy access. How could I diagnose this?



The only reason I would doubt it being a VSM is because I haven't had any other symptoms regarding a faulty vsm. My cab lights, cluster, door locks, and everything seems to work fine.

This is driving me insane, and I'll really need it to be fixed by February 19th. If I don't have it fixed by then, is there a way I can manually put the transfer case in 4Hi if I take off the t-case motor?

 

Ok here is what I found.

F350: I have an 08 F350 with 4wd switch on dash and auto locking

These are the readings I'm getting out of my switch.

 

These are the readings I'm getting out of my switch.

I'll probably just buy a new switch then and see if it fixes it... Although I would not be surprised if it doesn't, unfortunately.

To access the VSM you want to pull the Radio and remove the lower dash panel (with the cupholder and below). The Module is on back of the firewall, up high behind a metal tube, at the top of the transmission hump on 2 threaded studs.

Not the end of the world to get to... Apparently. Is there any way I can diagnose my VSM as working completely functional without buying a new one? And am I right in my research that it does actually in fact control the ESOF 4x4 function?

 

In my '02 I was surprised to find I had no VSM (it's a Basic work truck). So, the cablights, cluster (I have manual door locks) aren't controlled by the VSM but rather the Cluster itself. My TC is manual stick on the floor.

To access the VSM you want to pull the Radio and remove the lower dash panel (with the cupholder and below). The Module is on back of the firewall, up high behind a metal tube, at the top of the transmission hump on 2 threaded studs.

 

Did you ever resolve this issue? I have the same results in my 2002 EX. I have tried a switch that I know is good from another super duty. I can use a snap on MODIS diagnostic computer to switch mine in and out of 4x4 and low range, other than that I get no response from the switch and no relay click. The crazy part is it will occasionally work like its supposed to. Any thoughts and how did you fix yours?

 

kind of interesting that I find this post that is little over a year old and i am having problem with my Tcase. i was going to just put a new motor in but after a little research found out that it is more likely a fuze, relay or something else before the motor.

would like to find out what the issue was with the original posters results were with the problem of his transfer case. was it the switch or the VSM?

thanks

 

A buddy had this same problem but his was the vac lines

 

SOLVED:

The problem ended up being the transfer case motor itself.

Apparently I just didn't understand correctly how to test for voltage on the harness at the t-case motor. I wasn't registering any voltage at the harness because of user error. Oh well, living and learning.

Put in a dorman motor and works fine now. Glad to have 4x4 again!