I have a 96 Chevy Blazer I'm having difficulty with cranking it just put new starter and ground wire still not doing it mechanic said try to replace computer which is a long shot but I will try it can you guys think of something else that will make it do this

 

The PCM has nothing to do with engaging the starter. If you replace the PCM, you're opening a can of worms, don't do it.


Does the purple wire at the starter show battery voltage with the ignition in the START position?

 

Need more details of the problem; does the starter engage the flex plate when key turned to START? Or is there completely nothing, no "clunk", nothing form the starter?

Is there +12V at the big terminal on the starter? And as Captain asked above, +12V on the purple wire, small terminal on the starter when key is in the START position?

Need more info.

Oh...and find a different mechanic....that one is going to get you into trouble!