adjusting radiator electric fan thermostatic switch temp setting

[Michael C Henry]

I discovered that the electric fans were not coming on. It turned out to be the electric supply . I had a plastic circuit breaker bracket that held 2- 20 and 2 -30 AMP circuit breakers. 30 s on thee out side 20s in the middle. They were all connected by a copper bus bar. I used the left center as breaker post as mounting point for the in power supply on the bus bar. I clamped the bus bar directly to the plastic bracket with the circuit breakers. It didn't work for ever as I planned. I don't remember when it last worked. The electric connection must have not been tight enough and it got hot and started melting he plastic bracket breaking the electric connection. I repaired the bracket and just used the bracket as an organizer to hold the circuit breakers using a #10 fender washers with nuts. Then I used #10 internal external star washers on the breaker posts, then the copper buss bar, then star washers and nuts to create tight electric connections. I mounted the supply wire terminal with another star washer. The bus bar is now raised off the plastic bracket and is nutted tight to all the circuit breakers. The fans are actually fed by 2 Bosch relays, so the radiator thermostatic switches are only handling relay control current.

Now back to the radiator fan thermostat switches. Having not heard them running in a long time, I had doubts. the dash temp gauge shows the engine coolant temperature behind the engine thermostat. I figured how to check when the radiator fans are being switched on and off with a test light. But what radiator coolant temperature am I looking for ? How do I adjust for that? When should the radiator fans need to be coming on?

[RockBit]

The thermal fan switch on my ERA is marked 175F. It is in the middle of the lower radiator hose.

[Michael C Henry]

175° seems close to 195°, which is about where I want to stay around. At what temp do OEM set to turn on?

[strictlypersonl]

ERA places their thermo-switch in the return hose of the radiator. At that point, the water has already passed through the radiator. Water temperature entering the radiator will be regulated by the thermostat, ideally around 190F/87C.