Hey everyone - my SC has a little problem, when the temp guage hits 220' it doesn't kick the electric fan on. I replaced the sensor in the passenger side head but I basically have no idea which sensor controls the fan - any ideas? The car WAS a 305 TBI Sport Coupe, now it has a 355 in it.

TP

 

The impression I get is the same sensor was used in the pass side head for all years of 3rdgens... according to diagrams.. the head fan switch doesn't ground until 238°. From what I can tell too, the TBI ECM has no control to the fan.

Your best bet would be to replace the 'sensor' in the pass side head with a JET 200° (off at 185º) fan switch or just wire up a manual switch. GM intentionally made these cars run hotter than.. well.. you know

Even the TPI ECM controlled fans didn't kick on until around 220-225º or so. Makes a little sense tho when the OEM thermo is rated for 195° (opening closer to 200°)