So my van ran great, no problems. Then I went out of town for a few weeks. Now turn the key and nothing happens except the seat belt and battery lights come on the dash, no other lights or Guage movement. I tested the batery and it's fully charged. Tested power to the starter and to the ignition and they were both good. We jumped Power to the starter and it worked. Checked all the fuses under the dash and under the hood twice, and nothing. I even changed out the starter switch trying to get lucky, but nothing changed. My mechanic friend thinks it needs a new computer. Any ideas?

 

Here's a diagram, I assumed you had a diesel engine.

http://www.revbase.com/BBBMotor/Wd/D...dPdf?id=155319

Go down to page 2 of the pdf. On page 2 you will see the ignition switch, and coming off the start position you will see a block with "F" inside it. "F" is hot in start.

Go down to page 8 in the above pdf, you will find "F". It goes to the underdash fuse box where it goes through fuse 33, 10 amp, and then goes to the starter. See if this fuse is good. If it is, take a testlight and probe the fuse while it's in place, and see if the testlight lights up on the fuse when you spring the key to start.