I think there is something wrong with the fan portion of the ECM in these cars. My old 93 had the fans stop working unless the AC or defrost was on. So I changed to an SLP chip and 160 t-stat and they worked fine. Go to
www.camaroz28.com or
www.ls1tech.com and you'll find quite a few people having problems with the fans turning on. Do your fans come on when the AC is on?