The same thing just happened to me this morning on my 04 Sprinter. Did you ever find out the problem and the fix for it? Thanks.
An hour after I posted this, I took the batteries out of the key and switched them with newer ones. No good. Put the oldones back in and still the same problem. Checked the fuses for the ignition (took them out and reinstalled them,they were all good). There was a screw completely out of its place under the fuse hatch on the steering wheel. I screwed it back in after checking the fuses. Tried to start it and it started. Drove it around for about 10 minutes, no problem. Shut it off and restarted,noproblem. Took a 5 minute drive came back shut it off and went into the house for several minutes. When I came back out, the problem has returned. I am at a loss as to why it worked and now it won't. The van was towed to my home last night because it would start, but, not go in gear. Then this AM it had the same problem as yours. Glow light on and aux. fan screaming. Would towing it have caused the problem? Thanks.

Originally Posted by 04sprinter

04 sprinter will not start, turn key and glow light and normal lights in dash come and go but glow light never goes out and no crank. auxillary cooling fan comes on and stays on as long as key is in run position. Any help with this problem would be great.