I have a 1999 Express 3500 cargo van that I have owned for about 2 years now. The other day I went to start it and the battery was dead (been about a week since I used it). Put my jumper on it and it cranked and fired, but dies immediately. Tried again, same thing. Then I realized the security light was on. This has never happened before since I owned it. I changed the ECU about a year and a half ago and did have to reset the security then, but it went fine and have never had the issue again. Problem is, now I cannot get it to reset no matter what I do I've tried "key on for 10 minutes", "key on for 30 minutes", "key on for 10 minutes then off for 5 seconds, 3 times" and also "crank then leave key on for 10 minutes then off for 5 seconds, 3 times". Nothing is working. The light never goes out at all except when I turn the key off. What am I missing here? Also tried the "lock/unlock drivers door" trick too, but it is a cargo van with no power options, so I really didn't expect that to work anyway. Been messing with this damn thing for 2 days now to no avail. Any help is appreciated. Thanks