i have a 94 z28 with ok so we all now its an ODB1. Here is the problem, when i try to check the codes when the SES light is on by connecting the pins with a wire the SES light won't blink and let me know what the code is instead both fans kick on!!!!!!!! So what do u guys think the problems can be. If its checked with a scan tool it works fine but if I jumo it the fans kick on!!!!!!!!!

 

You can't do that trick with 94's and up. It will only work on 93's. All you did was put the PCM in service mode.