Looking for an auto temp switch for an electric fan

[Lonesome7.3]

I have been planning to convert all our truck electric fans. I was hoping to build a standard wiring harness to work with all of them using common parts. I do not want to use a store bought fan controller because of their reputation for giving out. I believe I have found, what I consider, the best option for what I am trying to do. However, I cannot find a design that eliminates the probe that sticks in the radiator. I do not want to go that route. However, any switches I find either tie into the ECM or require some kind of special hardware or parts that are model specific. Any thoughts or suggestions of this?

 

[That Crazy Squirrel]

I could probably Rube Goldberg something using an infra-red temperature reader, but it's not going to be any more reliable than one of those fan controllers you don't want to use. There's only so many ways you can read the engine temperature, and you're pretty much saying no to all of 'em.

A direct probe into the coolant stream is simply the most reliable and cost effective way to do it, which is why the auto manufacturers do it that way. You can either use your own probe, or use theirs, but that's the way to go.

 

[Lonesome7.3]

I agree. I would prefer to use a direct probe, just not stuck in the fins of the radiator. I like the screw in style if I had a place to screw it in.

 

[That Crazy Squirrel]

I agree. I would prefer to use a direct probe, just not stuck in the fins of the radiator. I like the screw in style if I had a place to screw it in.

That would be my preference as well. Getting the probe into the coolant flow is what will give you the most accurate and reliable reading. Those fin sensors are too subject to radiator cold spots, dirt, rain, snow, air flow, etc.

 

[That Crazy Squirrel]

Could try using a freeze plug location for a probe site. You'll have to rig something in a replacement plug to hold the probe, but it has potential. You might even be able to modify a block heater by removing the heater element and replacing it with the probe.

 

[Bigredmariner]

You probably have a plug on your intake or side of a head that would give you access to the coolant. I have installed and run similar switches to this one on the link before, use a relay to handle the load of the fan and use the temp switch to trigger the relay. Probably the simplest and safest setups you could do.

Afco 85287 Electric Fan Switch, 195 Degree On, 3/8 NPT - Speedway Motors, America's Oldest Speed Shop

 

[Black02Silverado]

I know on GM vehicles some had the probe stuck in the thermostat housing. One like this that you could drill and tap or find one with the threaded hole already in it.

 

[Lonesome7.3]

I was thinking about a freeze plug mod. I have a few ideas on how to make that work.

On the old Dodge i plan to do this to I might have a port in the head. But the two Fords I doubt.

Good to know a GM is like that. If I can get the GMC I have built I will do that.