Electric Fan T-Stat Switch


jeepjoe43

YJ Enthusiast
Joined
Dec 4, 2020
Messages
242
Location
Black Canyon City, AZ 85324
Just doing a little homework here.
Does anyone know the appropriate temp range for the fan switch with a 195 t-stat?
I was looking at an on at 205, off at 195 unit, does that sound right?
Makes sense in my mind, but I'm not an expert.
I'm pre-wired for 2 terminal unit, any suggestions?
 

Walt Jaquith

YJ Enthusiast
Supporting Member
Joined
Apr 12, 2020
Messages
104
Location
Lafayette, OR
With that range I'd put the sensor in the upper radiator hose or at the top of the engine to sense the coolant at it's hottest point, but I would think that would work. You'll have cooler fluid than that coming into the engine from the radiator, which is a good thing.
 
  • Like
Reactions: jeepjoe43
OP
jeepjoe43

jeepjoe43

YJ Enthusiast
Joined
Dec 4, 2020
Messages
242
Location
Black Canyon City, AZ 85324
With that range I'd put the sensor in the upper radiator hose or at the top of the engine to sense the coolant at it's hottest point, but I would think that would work. You'll have cooler fluid than that coming into the engine from the radiator, which is a good thing.
A friend of mine recommended putting it in the heater hose to the core.
I'm also looking at a PWM (Pulse Width Modulated) variable speed fan controller, though not very seriously.
I do have industrial experience with this concept, but not sure how that would work with thermostat.
But it cost's a lot more than a switch and would be more unwanted electronics.
Just doing homework. A toggle switch served me well for years.
 

Walt Jaquith

YJ Enthusiast
Supporting Member
Joined
Apr 12, 2020
Messages
104
Location
Lafayette, OR
I'd put the temp sensor as close to the engine as possible, but I don't see why that wouldn't work. Just make sure you get it in the send line, not the return. It would take a relatively hefty PWM/FET unit to run a radiator fan; those things pull a lot of current. I'm not sure the fine control would be worth the effort.

I've thought about getting an Arduino (or similar) microcomputer and programming it to run the heater fan, auto-on for the lights, wiper delay, and several other things of that nature, just for fun.
 
  • Like
Reactions: jeepjoe43
OP
jeepjoe43

jeepjoe43

YJ Enthusiast
Joined
Dec 4, 2020
Messages
242
Location
Black Canyon City, AZ 85324
I'd put the temp sensor as close to the engine as possible, but I don't see why that wouldn't work. Just make sure you get it in the send line, not the return. It would take a relatively hefty PWM/FET unit to run a radiator fan; those things pull a lot of current. I'm not sure the fine control would be worth the effort.

I've thought about getting an Arduino (or similar) microcomputer and programming it to run the heater fan, auto-on for the lights, wiper delay, and several other things of that nature, just for fun.
They do pull a lot of current, but it looks like it's built for it, again, I'm not seriously considering it.
The only fan failure I ever had was the relay, couple lengths of wire and some crimp connectors, good to go.
I had spare relay, but it got smashed to pieces in my tool box. I've learned a bit about packing a Jeep since then.
Thought about Arduino route as well, that's similar to how my Grand Marquis works. It's actually pretty convenient.
But it's a Luxo Cruiser.
I think simple is better, especially out in the bush.