help! mechanic just got a code 66 for 97 gc sport with 3.3L
:banghead:

Means that the body computer isn't or wasn't working at one time. If your gauges and instrument cluster are all working, disconnect the batter for a couple minutes to clear the code. Should take care of it.

Check for a water leak that may have gotten into the Body/convenience modules, or the keyless module not working (if you have)?