[Gear Grinder]

1992 S-10 Blazer. The push button on the dash for four wheel drive doesn't work about 70% of the time. The lights flash when you push it, but that's all that happens most of the time, other times it will go in. Checked dash switch for electrical connection and was good. Replaced electronic module under dash for the fourwheel control. Still same problem. Checked vacuum lines going to tranmission and electrical connections, they are making good connection.

Does anyone know where I can get a diagram and/or check list to trouble shoot this kind of problem? Even better, suggestions from anyone that may lead me to the problem. Much thanks.