AGreen

iTrader: (11)

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The lower driver's side is a switch, it's for the cold start assist feature. Like was mentioned above, it closes below 65deg. The one on the top of the radiator is the low level alarm. The one behind the thermostat is the sensor for the ecu. The one on the block below the oil filter pedestal is the sensor for the temp gauge, and the only one that should be left is another one on TOP of the thermostat housing. It's a single spade terminal switch for autos or turbos with the little factory push fan. If there's another switch that you have, then post a picture of it.

Wire colors are terrible indications that you've wired it up properly. You need to look at the relay terminal numbers. 85 and 86 are the terminals for the "electromagnet." So put +12v on 85 and 86 will go to the switch. Then 87 and 30 are for power and load, so put +12v on 30 and the blue fan wire will go to 87. Then ground the black fan wire. Then at the switch, if it has 2 wires run one to 86 and the other wire to ground.

(This is for future reference, if anyone searches this thread for answers. I see you've already gotten the wiring figured out.)

RotaryRocket88

iTrader: (7)

Ok, we'll try this again. Yes, the thing with 2 prongs on the bottom of the radiator is a temperature switch, but it's not for a fan. The guy behind the counter at NAPA has no information on what the switch is for, or what temperature it switches at. One prong connects to a wire running to the ECU, and the other runs to ground. It closes the circuit and grounds the wire to the ECU at about 65F. If you use this switch with a fan, it will pretty much run ALL the time. You might as well hook the fan up to constant power and ground if you're going to do that.

READ the thread Arghx posted in post #2. It has a gigantic picture of the single prong temperature switch that is used for fan switching. This kind of switch grounds through the body of the sensor.

clokker

iTrader: (2)

The single terminal switch is easily the most common but does have disadvantages in certain situations.
Since that kind of switch grounds through it's body, you can't use sealant or PTFE tape on the threads.
Two terminal switches (called "floating ground" switches) run power in and ground out, so they're not dependent on the switch body for the ground and are handy for switches mounted in rad hose adaptors or if you need/want to use thread sealant.

When choosing the trigger temp of your switch, remember that the thermostat isn't fully open till 192°, so anything less and your fan and thermostat are constantly at war. Given the inherent inaccuracies involved, I like 195° as the low speed trigger temp and that's worked out quite well in Denver's moderate climate.
A hotter climate or smaller radiator than mine (Godspeed) might need a lower threshold trigger to be effective.
Basically, my goals are to have the fan run as little as possible while keeping coolant temp below 200°.
In wintertime, my fan rarely runs and coolant temp stabilizes @180-185 (with the heater set to full HOT and blower ON).

blackrotary23

ok. so i pretty much need to find the one prong temp switch and locate it in the hottest part of the cooling system.

88evolFC3S

iTrader: (1)

dont go from the thermosensor on the bottom driverside of the radiator. it doesnt give you the best reading for the temp of the coolant in the engine itself. this is where i first ran my wiring for my efan and even though it works it doesnt come on like it should if you were to run it off the thermoswitch near the thermostat. here a diagram of how i wired mine and it now works great

like i said it will turn on your fan from the switch in the radiator but you should use the thermoswitch on the back of the thermostat housing.. take it from my experience