I think my computer is bad. Replacements actually aren't very expensive, but I'd like to try spare before I commit to the purchase. It needs to be compatible with a 94 K3500/automatic/4x4. Some stuff has corelated(sp) lately while I've been doing some electrical work and the computer has come into my sights. There's a connection between when I started having this problem and when I last handled the computer which was back when I was working on the blower motor. Soooooo, that's where I'm heading.