Putting in a a15 and i want electric fan where do i install theromo switch?

Put it in the radiator. Not the head.

Get one of these, the have a threaded hole for a temp switch. Put it in your tip radiator hose.
rad hose block.

In Australia a company called tridon make radiator caps hoses and sensors, switches.

They make a temp switch for OEM applications that switches on at we190 deg f and off at 175 deg f.

Just wire it up as per a normal switch, it takes care of the rest

Just go the the auto parts store. Ask for a temp switch. Just know your hole and thread size. Match your thermostat temp to the fan temp switch.
Go to the junkyard and find a radiator that will work that has the switch in it.

Electric Fan thermo switch can be installed two ways.
The factory used both of these methods in different years.

* in lower radiator hose
* in bottom of radiator

You can also wire it to run anytime the engine is running (much like a mechanical fan) and not use a thermo switch.

A15 factory installation



Nissan part number 21595-M0206


* Spec ON: 83-87° C (181-189 F)
* Spec OFF: 78-81° C (172-178 F)
* used with 82C thermostat (88C optional)

I used an aluminium joiner like unfam posted with a 70 deg NO temperature switch in the bottom hose. (http://www.ebay.com.au/itm/THERMAL-SW ... cb83&_uhb=1#ht_500wt_1054)

Min works fine, those switches are good for 10A. Another way would be to fix the switch onto the bottom (outlet) radiator tank.

You put it in the bottom of the radiator when replacing the mechanical fan so it switches on when the radiator outlet water is too hot, i.e. not enough air flow. You put the switch in the top hose when it's an auxiliary fan so that it cuts in when the existing fan isn't doing the job.

Thought the higher temp ones in the top hose,Like the thermostat if it was your primary fan