Does anyone know if a part like this is available off of a factory car? I can use this, but if I am on the road and it goes bad, the local parts store probably will not have this on the shelf. I would rather use a similar factory style switch. 185 on, 170 off

http://www.summitracing.com/parts/PRF-30111/

Thanks

I used one of these (http://www.ecklers.com/product.asp?pf_id=40415&dept_id=1252) in the El Camino. In the 5 years I owned the car it never failed.

The temperature range you want will run the fan all the time in the summer. I installed one that came on at 210 and off at 180 and it worked out great. GM has the fan come on at around 230 and off around 195.
I still have the lower temp switch 185/170. PM if interested in it.

BTW the switch can only be used to control a relay not carry the load of the fan.

Thanks, I plan to use a relay

I just went to the NAPA store and got a switch.
My fans (in the 59 Elky) do not kick on untill 225*----which is okay with me.
They cool pretty quick (twin Spals).
Also have a switch in the car to turn them on if I am to be in heavy traffic for any length of time. The car usually hangs around 180-190 when driving.

Interior switch is a good backup plan in the event of a switch failure----which I have not had yet.