I have a 2001 Impala 3.8, driving on the highway couple weeks ago very cold night, noticed temp gage (dial) was just about 150. Later that same evening returning home, gage went completely south, MIL came on and now the fans run on high when engine shuts down. Left fan motor is making noise (maybe bad brushes). Pull the codes > P0114 & P0117. Replaced the ETC & theromstat - No change. Scanner reading ETC @ 284 with sensor plugged in and 38 unplugged. Reading steady 5v ref with engine running. Not sure whats causing what problem...any suggestions out there....