Deborahheinz Report post Posted February 17, 2012 I have a friend and FMCA member with 1990 Chevy 454 on a P30 chassis having a problem with the cooling fan. The fan is running constantly and he thinks the sensor is faulty. Can anyone provide a diagram showing the location of the sensor? Thank you. Share this post Link to post Share on other sites
wolfe10 Report post Posted February 17, 2012 There will be two different fans: Engine driven fan which has a viscous hub clutch and an electric fan(s) in front of the condenser. The electric fan(s) are activated by the dash A/C and may be activated by a separate temperature sensor as well-- I have not worked on that particular model. Hopefully, someone with that model can give specifics on the electric fan circuitry. Share this post Link to post Share on other sites