This all started off with my stock temp gauge always bouncing between hot and normal operating temp. I figured I'd get a little better gauge and replaced it with an electric autometer unit. I just eliminated the stock temp gauge and used the autometer sending unit in the stock location under the distributor. It still shows the temp gets upto 240f and sometimes 250f when driven slightly hard.

The lower hose was not getting nearly as hot as the top, so I replaced the thermostat. Lower hose gets warmer now. Still no fan though.

I jumped the two wire plug that leads to the ECT swith by the thermostat housing, and fan turns right on.

If I'm correct, that eliminates the fuse, and the relay. I thought it had to the the switch, and it's only 20 bucks. I replaced it. Still no fan.

The fan switch temp probe and the autometer probe are in very different locations. The autometer is right into the head. The ect switch is by the thermostat. What I'm wondering is, can the radiator be cooling so well, that by the time the coolant reaches the ect switch, it's not hot enough to kick fan on? If autometer reads 240f in the head, can the radiator cool it enough to get below 191f (ect switch should turn on at 191f I think) when it reaches ect switch?


Although the car runs great and does not overheat to the point where I have to stop driving, I'm worried that when summer heat is involved, it may boil over on me.

 

so you put power directly to the fan and it turned on? that doesn't eliminate the fact that the fuse and/or relay could be bad? have you checked those yet?

 

From my understanding, when I jump the ect switch, it does not bypass the fuse or relay. When I jump the connector, the fan turns on. While the fan is on, if I pull the fuse or the relay, the fan turns off.