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Electric Fan Temp Switch

dhcomp

dhcomp

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What is everyone using? I have read numerous posts debating what fans to use, how to wire them, etc, but not much on what temp switch people are using. So lets get this thread focused on the switch itself, not what temp, which fan, how to wire.
I plan to turn on at 200 or 210, and off at 185ish.

Here are the options i see

Painless 30110 $38 - Temp sensor, 2 wire, completes circuit when its supposed to be on
http://www.jegs.com/i/Painless/764/30110/10002/-1

Jegs 10563 $24
1 wire sensor, grounds to radiator. Do these normally work, or is the radiator a $hitty ground. An easily improved ground?
http://www.jegs.com/i/JEGS/555/10563/10002/-1

Jegs or Painless adjustable $27 - stick in radiator type probe, adjustable (which i dont' really need), but practically cheaper than other setups
http://www.jegs.com/i/Painless/764/30110/10002/-1
or
http://www.jegs.com/i/JEGS/555/52125/10002/-1


I'm thinking the 2 wire painless threaded plug setup is the way to go, but want everyone's opinions.

Also, should this go into the radiator, or manifold? Is there a spare coolant temp port in either place? If so, what thread is it? Would adjusting the thread side with an adapter screw up the ground on the 1 wire sender?

I don't think the A/C turns on any fans on my 91 in the stock setup, what wire would i need to tap to turn on one of the fans whenever the A/C is on? I'm guessing one of the compressor wires, but have no idea which one.

Thanks guys!




BTW, I have windstar fans on the way. Hope to keep the engine cool and free up a little power when towing up grades.
 
Put it in the engine. Adapter shouldn't be a big deal, although it might affect how fast the sensor sees temperature swings. As GM went up to 220* in stock form, that gives you a large amount of leeway if you are looking at a 200-210* off point.

I doubt the '91 has a spot in the intake that is unused, you can use the one in the passenger side head, same one as on the drivers side for the gauge, just further back.

I didn't wire anything "additional" up with my electric fan setup, but I wonder if you couldn't simply splice the temp switch and AC signal wires together before the relay, so that a ground on either circuit would trigger the relay and thus the fan. No idea if the AC circuit has something you can use like that, but I'd expect it does.

From some accounts, the electric fans are lacking while towing up hill, however back when this was being discussed, I'm not sure the "good" factory electrics were being used. Aftermarket electrics commonly used seem to be too small many times.
 
Those probe style adjustable switches are what I'm using on my setup. I've got two fans on two switches, with one having a manual power switch, the other coming on with the ignition.

I like the adjustable switches because I can "fine tune" the setup anytime I need to. The primary comes on roughly 200* and the aux at roughly 210*. This way if the engine is running hot under load, the second fan comes on to help with cooling duties. Otherwise the primary handles it just fine.

The probes on mine are in the radiator, but at the top which probably isnt where they should be, but it works out ok as they shut off once I'm cruising down the highway.
 
I used this one with just a single wire switch. Why do they need a second wire?

http://www.painlessperformance.com/webcatalog/largeview.php?SearchField=30102

Just make sure the fans are set to turn on at a temp above what your thermostat is rated for, otherwise they'll never turn off.
Jegs 10563 $24
1 wire sensor, grounds to radiator. Do these normally work, or is the radiator a $hitty ground. An easily improved ground?
Click to expand...

Actually, that one looks closer to what I used. It doesn't ground on the radiator though. It goes into an open port on the manifold or the head.
 
I use spal PWM module. Found it really easy and got it for under 50. Really easy hookup for both fans. Hooked into the line for temp gauge and set the low and high as instructed. really easy and works great.
 
I first though radiator cause that is where the one in my old bimmer was.

So not installed in the radiator. ok.

People keep referencing using stock parts in the 200-210˚ range, what vehicles came with these? And how can i figure out what the thread size or operating ranges are?

The spal controller looks sweet, but i don't want to spend that kind of money.

I think im going to get sensors, wire up with a/c, etc, but no install the fans for a little bit, and run idiot lights so i know when each fan is expected to kick on. Then, once all teh kinks are worked out, ill drop the fans in, and hopefully avoid most of the switching problems. THanks!



Thanks guys!
 
Ebay has the controllers for around 65 bucks right now. Once you setup everything you'll appreciate how chceap that really is. Or once you forget about your idiot light on the dash and cook something. :doah:

Their are other methods as people have suggested as well that work great. You can save a few bucks but I just wanted to tap into a sensor that was already there and have it work right away. My passenger side head plug didn't come out it's fused into the head so I was limited on options.
 
I used this...

http://www.summitracing.com/parts/SUM-890017/

or you can use this...

http://www.summitracing.com/parts/SUM-890018/

They look the same as the Jeg's one to me.


I don't like the type that go into the radiator fins, why add another variable, and they can get plugged with mud or something. It's the coolant temp you want to control, not the radiator fin temp. Add a $3 relay and your done, and possibly an override switch to manually engage if you prefer.
 
The reason I went with the fin type is that my engine hits 200* before the t-stat opens and once it does all the coolant in the radiator drops the temp to about 170*. So if the sensor is in the block the fans would come on (unless I used a much higher temp sensor) when they dont need to. By using the radiator temp to switch the fans, they only come on when the radiator is hot. It also allows the fans to shut off when cruising at highway speeds. The dash gauge is still showing the block temp, which is what I use to ensure the fans are cooling properly.

My setup works quite well as the temp rarely goes above 210* and the fans only come on in slow traffic or when the vehicle isnt moving. I also have idiot lights for both fans tapped in after the relay. This way I'll know if the fans dont come on due to bad temp switch or relay.
 
I got lucky enough one day at Napa to have one of the folks there hand me their Echlin catalog that contained temp switches and senders. The catalog showed the details for most all of the temp switches that was crucial...on/off temps, thread size, connector style, etc.

Most any Napa should have the catalog I'd think, just wish it was online. It's been a couple of years, hopefully they still put out the same thing.

I know the Buick Grand Nationals used the lowest temp switches GM ever put on a vehicle, coming on at 195* if memory serves, but that's too low if that's your t-stat temp.

Camaro's used switches, I suspect the carbed cars and MAYBE the TBI cars to have used a temp switch for the primary fans as well. TPI primary fan was controlled via ECM while the secondary fan was controlled by a temp switch that comes on at something like 240*, so those won't work. Look at '85-92 applications as a start, although much of the FWD stuff might work as well.
 
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