Ok, I don’t have this sensor on the block (it goes on the back of block to the slight upper left of the oil filter) nor do I have the plug hooked up. So far I have no CEL. It was recommend by another member that I don’t need to run this switch. What does this switch do exactly? Does it turn on the A/C fan when the engine reaches a certain temp? TIA for the info.
yes that is the temperature switch for the coolant fan…You may have one that connects to the thermostat cover…I know when i did my b20 swap, the b20 doesn’t have one on the block…It is actually on the thermostat cover ( obd2 connector ) So i had to get a obd2 connector for it to work…What year block are you using ???
leeo
I do have a connector at the thermostat housing and I have that connected to a plug from the harness. But would that compensate for the missing oil temp switch in the back of the block to turn on the A/C fan? Isn’t the oil temp switch a sensor that gets signal from the oil temp and not coolant temp? I would think if there is a connector on the wiring harness that needs a connection at the oil temp switch and one at the thermostat housing, they each do separate functions?? What do you think? TIA for your replies.
If you have a 92-93 the switch is on the thermostat…thats the switch that tells the fan when to turn on…If u have a 90-91 then its on the block. Depending on what year car you have, you should defintely have 1 or the other, unless u like to watch ur baby overheat =(
Another thing…the a/c fan turns on right away as you turn on a/c…that fan is connected to the condensor.
i’m trying to figure out this mystery of the dissapearing oil temp switches (for b18b and b20 swaps). My 1990 didn’t have one but some '91’s do.
This is NOT the coolant temp switch that is relocated to the thermostat housing in later gens. This is an oil temperature switch, the third in the trio of sensors beside the oil filter (in the middle and closest to the crank pulley side of the engine).
Do swappers just leave that connector hanging?
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Still no answer:( I am in the same situation here. SHould I just leave the oil temperature swith unhooked? Will it cause any CEL or malfunctions of any sort?
Much needed reply asap. thanks! 
This question was just addressed about 3 posts ago. There is an Eng Oil Temp switch that turns on your condensor fan when the oil reaches a certain temp whether your ac is on or not. It operates just like the Eng Coolant Temp Switch that operates your cooling fan according to coolant temp. Wish I had an answer on how swappers handle the EOTSwitch.
I suppose I am a bit confused then. I am refering to whatever the switch/sensor is that has the two prongs on it and is within the group of three. It has a green base and also shars the hershey kiss style cover. Once removed, there are two wires that remain…I beleive one is green and the other yellow. This is my only concern, as the others all swapped out fine.
The green plug you are refering to is the engine oil temp switch I have seen people leave it hanging , but I ran the wires back into the car to a switch so I could turn the fan on at will .