fan switch wiring, what am I doing wrong? (1 Viewer)

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I bought a JET brand fan switch from Summit, and am wondering what I am doing wrong with wiring it up.

The switch is going to a relay, then powering the fan from there. I tested the switch itself, and when my gauge said around 210*, the switch was not "grounding" or whatever you call it, at all- current would not flow from the metal surface on the outside of the switch at the threads, to the wires connector pin.

So, my question really is- at 195* should this switch ground 100%? I thought thats what it should do, but I havent been able to get it to do it. And if not, what does this switch do then? Is the switch just not working?


What am I missing?

thanks!
Dustin
 
If the switch is supposed to kick in at 195 F, then it should read zero ohms above 195 and it should be open below that.

What is the temperature rating of the switch?
 
its supposed to be rated at 195* on, 185* off. My temp sending unit is on the side of the block (tbi'd chevy SBC 350), and this switch is right near the thermostat in the intake manifold. So, I suppose its possible there is a slight difference in temp between the two areas, but 15* seems like alot to me. Perhaps my somewhat new VDO temp sender is just plain wrong.

When I tested it, I didnt test for ohms, but just the plain ole' buzzer feature my ohm/volt meter has.

crappy diagram of how I tested it:

thanks!
Dustin
fanSwitch.jpg
 
How many conectors are there in the top? If there is more than one, maybe the brass is not gounded and you need to check for continuity between the wires in the top.
 
You didn't use teflon tape around the sensor to seal it, did ya??
 
I didnt use teflon tape. My tests indicate the outer part of the switch is deffinitely grounding to the motor too. But regardless of all that, it seems the switch is just not opening the circuit from the wire to the outer base.

I'll call Summit today to see if they'll send me another switch.

thanks!
-Dustin
 
The switch needs to have a relay. If you dont use one the switch will only work for short time before it shorts out.
 
Old post Same Issue

Old thread, but search dose that.


Got one of these Jet switches from summit. Bastard turns on at 210 and off at 200. Soo tired of junk not working right.

I figured that it could of been my temp gauge in the truck reading bad, so I brought it inside to the kitchen after the :princess: left for work.

I tested the switch with an ohm reader, boiling water and a thermometer. And with the knowledge that water boils here at sea level at 212 for a sanity check, I reasured my self that the thermometer was accurate.
Yeap, the jet switch is junk.

One good thing is, I now know the water temp gauge in the truck is right on.
 
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The plain ole buzzer feature is to check diodes. Will buzz and than flip the test leads over and it should not buzz. However, you can check for continuity as well. Check the temp sending this way and flip the test leads and see if it buzzes in both ways. If it does not you know the sending unit is not doing its job.
 
The plain ole buzzer feature is to check diodes. Will buzz and than flip the test leads over and it should not buzz. However, you can check for continuity as well. Check the temp sending this way and flip the test leads and see if it buzzes in both ways. If it does not you know the sending unit is not doing its job.

:meh:

It's turning on and off, just not at the stated temps.
 

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