Roadster builders - Speedhut + Ron Francis? Need help figuring out wiring

[edwardb]

This weekend I spent some time trying to get the thermo switch to work and failed.

"To incorporate the Painless switch take a pigtail from the brown wire at the toggle and run it to one terminal of the thermostatic switch. Take another pigtail from the orange wire at the toggle and run it to the other terminal of the Painless switch."

This didn't work. It's not a painless switch, it's a thermo switch I got at the parts counter at Ford. The way it's put together I don't understand how the thermo switch can switch the power to the fan on. I did exactly as described: I took each wire from the toggle switch and tied it in to the wires on the thermo switch. I can still turn the fan on by flipping the switch but after letting the motor warm up the fan didn't kick on automatically.



EDIT: It did cut the looped wire on the back of the tach and that "calmed it down". Thanks for the tip Jeff.

The recommended Painless switch (#30110 or 30111) are a type of thermal switches, each with difference on/off heat ranges. But they are a simple on and off switch. They have two terminals. The two terminals are open until the target on temp is met, then they close completing the circuit and starting your cooling fan. Same as the manual switch on your dash. When the lower temp is met, they open back up turning off the fan.

Does the sensor you bought have one terminal or two? Many are only one terminal, and when closed are switching to ground. Another way to work the circuit but not how this one from Jeff (which I also used) works. Also, do you know the rated heat range for the Ford switch you bought?

On a side note, I'm actually looking for an alternative to the Painless switches. They are, unfortunately, not very accurate. I have had several of both part numbers, and the on and off points measure quite different than how they're rated. I've been back and forth with Painless tech support over the past week or so. They measured all the ones they had in stock and they also were quite a bit off. Like 10-15 degrees. I suggested they either needed to change the ratings or talk to the manufacturer (marked made in Taiwan) and tighten them up a bit. No response on that one. Similar negative reviews on the Summit website.