fan switch on open radiator conversion

I have a 1990 and did a open system conversion. I went with the new t-stat housing and put in the new factory fan switch. I cut the wires off of the old switch that was in the radiator and spliced into the new one.

well the problem is the electric fan wont come on when it gets hot at idle. And this is just before red on the guage. I unplugged the sensor and jumped the wires coming from the old switch and it fires right up. I also replaced the relay. It also somes on with the ac. but plug it in and nothing. the the fan switch in the t-stat housing it brand new.

any suggestions?

thank you flag2442

"If you'll use a late model thermostat housing intended for the factory fans switch you can use a fan switch for an '81 to '82 corvette with a 350 to control your electric fan! (The late style thermostat housing can be seen here. I have a drain petcock installed in the sensor port.)

Just ask for Borg Warner part #TFS19 or Niehoff part #DR137XL.

All you need to do is plug it into the late model thermostat neck, extend two wires to where your original fan switch plugged in using same method as below.

This switch turns the fan on at approximately 215 and off around 195.

Full Credit for finding this out goes to Avanteone (John) who posted this information on J.U. The actual text of his post is buried somewhere in the J.U. archives and is listed here only for informational purposes. No credit is claimed for finding this information! Many of us beat our heads against the counter at several auto parts houses trying to find exactly what John figured out! For more details, please go to J.U. and search for his user name and this subject."

source: http://www.lunghd.com/Tech_Articles/Cooling/Electric_Fan_Generic_Thermostat.htm

I haven't tried this yet but I intend to when I get a chance. I encountered the same thing you did. The new switch would not work. And I have read that it wasn't designed to do so. Kinda weird.

I'm running a toggle right now and so I'm happy.

Thanks I will try it
flag2442

The stock T-stat houseing switch is a resistive element that feeds the ECU and not a switch.

The T-stat houseing has a 3/8-18 thread which will fit almost all of those aftermarket temp switches from; Painless wiring, Hayden, derale.....

You can get them with variable temp controllers also.

Well I got the new switch and it has not turned the fan on yet well over 210 on the guage. Maybe its just not hot enough yet. Every thing else is working. The electic fan turns on with the ac and if I unplug the switch and touch the wires together it turns right on. I guess only time and temperature will tell.

flag2442

Well ive gotten very hot and it still does not turn on. I just put a manual switch on it and i am done messing with it.

flag2442

i JUST finished a 6 hour drive from san diego to central cali, and i can tell you that IT DIDNT WORK FOR ME EITHER!!!!.
I crossed the number at the borg warner web site and i came up with napa number ECHFS107.
It went right in the newer t-stat housing but it didnt turn the fan on when i needed it.
Any one else have any bright ideas??????
I wired it inplace of the oem non H.O. switch

I remember reading about a late-model corvette temp switch that will fit the newer housing and handle Renix fan duties. It was on somebody's XJ closed/open cooling system mod page?

I used a universal thermo switch from AutoZone on my open radiator conversion. It cost about $20, and the temperature that it switches can be adjusted. I simply fabricated a mount for the temperature probe behind the radiator, rather than insert it in a radiator hose. It works perfectly.

frsno jeeper said:

i JUST finished a 6 hour drive from san diego to central cali, and i can tell you that IT DIDNT WORK FOR ME EITHER!!!!.
I crossed the number at the borg warner web site and i came up with napa number ECHFS107.
It went right in the newer t-stat housing but it didnt turn the fan on when i needed it.
Any one else have any bright ideas??????
I wired it inplace of the oem non H.O. switch

Click to expand...

check out teh bottom of this link I totally bypassed a regular sensor and used and adjustable fan control the sensor tube mounted under the edge of the electric fan, worked trick and never had any problems again. had teh fan turn on at 195*

I did not run the switch on mine

cooling system conversion