Does my 94 JGC have a PCM and can I read the codes? If yes how and where? My dealer says he cannot trouble shoot my problem because his computer will not let him into my system???????

Yes your jeep does have a PCM (powerTrain Control Module aka Computer) and yes you can extract the codes yourself.

turn the key ON, OFF, ON, OFF, ON, - leave it on this time. The CHECK ENGINE light will begin flahsing count the number of flashes and pauses.
Post them here and Someone else or myself will let you know what the codes mean.

ok well i have a 94 Grand Cherokee and it has the trouble code 51. can someone tell me what that means?