another renix fan switch?yada,yada,yada

I was toying with a renix fan switch I got from the j/y today.I put it in water that was starting to boil and put my multimeter on it.The switch closed at approx.
210*

Now I know that the factory location is in the cooler side of the radiator and this is why it doesn't turn the factory fan on until 220*
What I am looking at doing is plumbing it into the heater hose that goes to the heater core so the coolant will be the same temp as the coolant in the motor.If everything works as I think it will my dual fans should come on at
210*
Correct?

I would go with the 83corvette switch that closes at 215* but I want my fans to come on at 210*I also should mention that I don't want to go with an aftermarket fan switch either for cost reasons.

outlander said:

I was toying with a renix fan switch I got from the j/y today.I put it in water that was starting to boil and put my multimeter on it.The switch closed at approx.
210*

Now I know that the factory location is in the cooler side of the radiator and this is why it doesn't turn the factory fan on until 220*
What I am looking at doing is plumbing it into the heater hose that goes to the heater core so the coolant will be the same temp as the coolant in the motor.If everything works as I think it will my dual fans should come on at
210*
Correct?

I would go with the 83corvette switch that closes at 215* but I want my fans to come on at 210*I also should mention that I don't want to go with an aftermarket fan switch either for cost reasons.

Click to expand...

Do you know if you can use the temp sensor from a 91+ that is in the thermostat housing and have it mate up with the RENIX system? Its a shot in the dark, but i wonder if it would work. Then all you would need is the sensor and new housing...

outlander said:

I was toying with a renix fan switch I got from the j/y today.I put it in water that was starting to boil and put my multimeter on it.The switch closed at approx.
210*

Now I know that the factory location is in the cooler side of the radiator and this is why it doesn't turn the factory fan on until 220*
What I am looking at doing is plumbing it into the heater hose that goes to the heater core so the coolant will be the same temp as the coolant in the motor.If everything works as I think it will my dual fans should come on at
210*
Correct?

I would go with the 83corvette switch that closes at 215* but I want my fans to come on at 210*I also should mention that I don't want to go with an aftermarket fan switch either for cost reasons.

Click to expand...

Obviously, tthat switch is bad. I am using a fan switch from the Renix era, the large one found in the radiator;......Is this the one you are refering to? Mine come on at 185* and and off at 170*. Mine is installed in the cool side of the radiator. In this location, the fans come at when the guage reads about 210* which is about 20* lower than the ECM turn the aux fan on.

yes that is the one I am talking about.How is it turning your fan on at 210 when everyone else around here has said that it switches the stock fan on at 220*?The switch that I have isn't bad,it shows an open circuit until the water I had on the stove in the pan hit 210*then it closed completing the circuit.I'm confused.

Maud:The newer switch for 91 up is more of a sender than it is a switch so it won't work.I found that out for myself after I installed a newer style thermostat housing into my 89 renix and tried to get the newer sender to turn my fans on.On the 91 and up xj's the computer receives a signal from the sender mounted in the thermo housing then in turn the ecm sends the signal to turn the fan on.

I was at home depot alittle while ago and couldn't find a tee that the renix switch would thread into.
Anyone have the thread pitch and diameter of the renix switch handy or know of where I can get a tee that will accept it and mount inline the heater supply hose?

Well, the fact that your switch closes at 210* and the one I am using closes 185* is unexplainable. There has to be something different about the two switches.
You are correct, the switch is open until the water temp reach the predetermined temperature then it closes. I have the one in my XJ in the lower radiator hose. It is wired to a relay which turn the fans on.

Think about this in the OEM application,........ the switch is located in the coldest part of the cooling system. If this side of the cooling system, the coolest side of the system get up to 210* would you not think the top of the engine including the head would be about 30*+ higher? This would be too hot for the XJ. I do not think DC engineered the XJ to run this hot.

Get another switch and test it. I have been running this setup for more 3 years now. The guage on the dash never get higher than 215* before the fan is turned on.

Muad'Dib said:

Do you know if you can use the temp sensor from a 91+ that is in the thermostat housing and have it mate up with the RENIX system? Its a shot in the dark, but i wonder if it would work. Then all you would need is the sensor and new housing...

Click to expand...

You should be able to - just extend/adapt the wiring from the OEM switch, and leave the OEM in place to keep the thing from leaking (there's a plastic plug that ships with new radiators, but I don't like plastic...)

As long as it's a "switch" and not a "sensor," you're in good shape. A "switch" is, obviously, an ON/OFF deal. A "sensor" is a thermistor that provides a variable resistance in response to temperature variations. Doesn't work so well for tripping relays...

techno1154 said:

Well, the fact that your switch closes at 210* and the one I am using closes 185* is unexplainable. There has to be something different about the two switches.
You are correct, the switch is open until the water temp reach the predetermined temperature then it closes. I have the one in my XJ in the lower radiator hose. It is wired to a relay which turn the fans on.

Think about this in the OEM application,........ the switch is located in the coldest part of the cooling system. If this side of the cooling system, the coolest side of the system get up to 210* would you not think the top of the engine including the head would be about 30*+ higher? This would be too hot for the XJ. I do not think DC engineered the XJ to run this hot.

Get another switch and test it. I have been running this setup for more 3 years now. The guage on the dash never get higher than 215* before the fan is turned on.

Click to expand...

Not arguing here but I don't see how your fans are comming on at 210* mounted in the lower hose because it is essentially the same as having it on the cooler side of the radiator.Are you sure that is a renix switch???How did you plumb the renix sensor into the lower hose

I've got the wiring down in my head,it's pretty simple actually.......
I am aware that there is a hot side of the radiator and a cold side.That is why I don't want to use the renix switch in the stock location(on the colder side) because it will turn my fans on too late....around 220*

I want to install it in the heater supply hose that runs to the heater core so in theory the coolant in that hose would be the same temp as the coolant in the motor.If I could just find a tee that will accept the renix sensor and splice that into the heater hose I should be good to go.

Anyone know where I can get a tee like that?I thought about brazing the renix switch into a copper tee that I seen at home depot today but don't know if the heat from brazing will kill it.
I guess I could solder it but don't know if I trust a soldered joint to withstand the pressure in the cooling system.I don't want to redneck engineer this.......

My XJ being a '96, the radiator do not have the provisions for the fan switch. What I did was to get the fitting for the switch from an old radiator at the U-pull-it here in Miami and braze it into a short pipe. The pipe is then inserted in line between the radiator and the water pump.

To wire this I used 12 volts from a good ignition source to supply the switch. When the switch closes, it provides a +12 volts to a relay coil. The other side of the coil is grounded. The load side of the relay is supplied from the battery via a fuse then to the fan. (I do not have a drawing. It is wired like any other relay.)

I would have prefered to use a radiator from the Renix era XJ. They have the fitting for the switch built in. I guess there may be some restriction in the cooling system caused by the pipe inserted between the radiator and the water pump. If this is true, it is not very obvious.

Check your switch or another switch. There may be different switches out there.

naw there is a much simpler way to do it like mine is.get a thermostat housing from a 91 up 4.0 it has the threads in it all ready for the crysler comp system,get a switch from here-> www.rodneydickman.com/n20.html
and screw it in the t stat housing and wire in a relay to the stock fan or what ever your running.it works very well.........

cool i just saw you already have the newer t stat housing-just get the sensor

Did you read the last sentence in my thread starter?

I know you said you dont want to go aftermarket but the cost really isnt that much more than a RENIX sensor and having the adjustability is nice.

Hayden adjustable control kit (90*-230*F) P#3647-----------$39.99
Factory RENIX fan switch------------------------------------$37.99
prices from www.partsamerica.com

Sounds like you didn't read the whole thread either......
free vs. $40 pretty big difference.