Fan switch

:screwy:ON MY 03 IMPALA I'VE BEEN HAVING PROBLEMS WITH THE COOLANT FANS SO SOMEBODY SAID CHECK THE FAN SWITCH WELL I CANT SEEM TO FIND IT..AND I REALLY DONT KNOW HOW TO CHECK IT OR THE COOLANT TEMP SENSOR THANKS..

There is no fan switch, the computer commands the fans on at 223 F.
To test the fans, disconnect the connector at the coolant temperature sensor, the fans should come on.
Check the relays in the under hood junction block.

You can test the coolant temperature sensor with a ohmmeter.

212F--177 Ohms
194F--241 Ohms
176F--332 Ohms
158F--467 Ohms
140F--667 Ohms
122F--973 Ohms
113F--1188 Ohms
104F--1459 Ohms
95F---1802 Ohms
86F---2238 Ohms
77F---2796 Ohms
68F---3520 Ohms
59F---4450 Ohms
50F---5670 Ohms
41F---7280 Ohms
32F---9240 Ohms
23F---12300 Ohms
14F---16180 Ohms
5F----21450 Ohms

:screwy:ON MY 03 IMPALA I'VE BEEN HAVING PROBLEMS WITH THE COOLANT FANS SO SOMEBODY SAID CHECK THE FAN SWITCH WELL I CANT SEEM TO FIND IT..AND I REALLY DONT KNOW HOW TO CHECK IT OR THE COOLANT TEMP SENSOR THANKS..

see what bozr stated ,,,fans commanded to come on at 223deg f...so if the a/c is off the temp is 190 deg f the fans WILL NEVER come on...


the fan switch is a relay ...the relay coil is fed from the pcm computer based on the pcm inputs which will cause the fan[s] to come on depending what else is getting hot or high in pressure...

thanks aleast now im getting somewhere....