having problems replacing icm.

You could always try a junkyard. Sometimes the made in china crap that places sometimes sell just doesnt work. Youll get it cheaper there too. Of course it could also be that the ICM isnt the problem. If you have replaced it multiple times from multiple suppliers and you are still getting the exact same problem then the problem may be somewhere else.

Thank you for the prompt reply. I perhaps did not clarify that I tried replacing the part yesterday at 4 different stores, placing the old one back in to go between them. None of the four replacements would start the van but when I put the old one back in, the van would start. I have all the right info for the van and even tried to cross years in case there was a different computer replaced at some time or initially installed from old stock at the plant. None of the mechanics or tech people I've spoken to have ever heard of such a thing and yet here it is a seemingly unsolvable problem. I will try a junk yard though as there may be another original GM icm among the dead.