Quote Originally Posted by enjenjo View Post
If you are happy with the way it runs, just leave it. But if you want all that you can get you will probably have to rework the harness for the right pin outs, and replace the PROM, or go to an aftermarket harness.
40Chevy,
It sounds to me like enjenjo knows the specifics here, and he warns that if you want to wire in your coolant sensor you will probably need to rework your harness for the right pin outs, replace the PROM or go to an aftermarket harness. Someone probably took the easy open loop mode in the past, and now you either leave it alone, or dive in and do it right.