Topic: One wire temperature sensor - need help wiring

[darthekai]

I have a motorcraft single wire temperature sensor on my tractor motor, and i want to use it to turn on a fan. As far as i can tell, it's resistive ie the resistance drops as it heats up. I have a relay to turn on the fan on a switch, do I need a pot or something to set a "trigger" resistance? Or can I simply run the ground from the relay coil into the sensor?

Interbutts aren't much help.

A bit out of my wheel house with this whole 1 wire dealy.

[RockThePylon]

You have an NTC thermistor, and you want a relay to click when the thermistor resistance reaches a set point?

[darthekai]

Hmm I guess so.
It used to drive the dash temperature gauge. I suppose it's grounded through the threads.

[RockThePylon]

If you don't need/want it to read water temperature, replace it with a switch. Might be the least hassle.

Otherwise, you'll probably need a circuit to trigger the relay. A temp sensors resistance will be pretty high, I doubt it'll ever flow enough current on it's own.

[darthekai]

I was considering re-wiring this to trigger the relay.

https://www.amazon.ca/gp/product/B00BLZ93T2/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1


The biggest problem is that I cannot find a "coolant temp switch" that tells me what temperature its going to switch at.
Descriptions are all as helpful or less than this:
http://www.autozone.com/cooling-heating-and-climate-control/temperature-switch/duralast-temperature-switch/128785_0_0_5673

[darthekai]

so since my car runs a 195 tstat, I should get a thermo switch between 205/215 and 215/225. Apparently, because auto value forest lawn uckfayin rocks and they have mountains of old books, a GM 25037089 is a 2 wire bladed thermo switch with a 3/8" NPT connection that operates over 210/219. Otherwise known as TS217.

This is not available anymore:( but it is listed as in Chev 87-83 and pontiac 87-83 theinternet tells me that this part should be in a firebird 82-91, transam 92, or camaro 82-92. The old dudes memory says "in those ohh 2.8? 2.0? pontiacs and chev s series? maybeee a sunbird, citation, or a celebrity, something like that. Yeah, look for those small engine front wheel 80s cars".

So i might do a trip to PnP later this afternoon.

[darthekai]

I should just do this. This seems like a way better option

Unless it's like a hundred dollars.

[RockThePylon]

That's what I meant by switch. A temperature sensitive one.

[darthekai]

hmmmm  of course the only one of the car i want is in the middle of a lake. But it gave up some goods.
The real question is, I tested it and it was OL on resistance up till about 160F then started falling up to 100C. I added some salt but the highest I could get was 190Ohms.
IS THIS IN FACT A TEMPERATURE SENSOR NOT A GODDAMN FAN SWITCH? based on the fact that the dash has a temperature GAUGE, yes.

plz respond.








Is it wrong I kind of like this car?





I saw some gems in the parking lot. A turbo VW wagon, a VW with a limited edition ARIZONA exhaust tip, and a super expensive landrover but the owner decided to build a snorkel out of stuff he found under his sink?

[darthekai]

Update: I am dumb. Wasted $6.

[RockThePylon]

That sounds like a sensor, not a switch. Even though 190ohms is pretty low for a sensor.

Just go to Mopac and ask them. They probably have 100 of what you need.

[darthekai]

You'd think that but no.  the best they can do is say painless fan wiring kit which is a disgusting $80. They have one yes one Thermo switch and it's like $16 but it's for the wrong temperature range something like 160 degrees Fahrenheit to 180 degrees Fahrenheit

[RockThePylon]

http://www.ebay.com/itm/200-Degree-Radiator-Electric-Engine-Thermostat-Temp-Switch-New-For-Cooling-Fan-/111797324728

[darthekai]

Ok..  but that's not a very convoluted solution. 

[RockThePylon]

I thought you wanted to tap off the sensor your ECU uses to read coolant temp, and have that trigger the fan. I assumed you were limited by bungs or whatever to tap into and wanted to DIY some solution for fun.

But if you have a hole to stick it in, and just want something that switches on and off when your coolant reaches a temperature. Well, that itshay is cheap and easy and everywhere.

[darthekai]

I am trying this new thing where I make do with what I have cuz like I have so much random junk.

But I was fully committed to a narrative that a switch at the right temp range is impossible to get or expensive.
For $8 that's a pretty good solution. Although I wish it was two wire.